Contagious Cancer Found in Dogs

Dan East writes "Scientists in England have gathered definitive evidence that a kind of cancer in dogs, known as Sticker's sarcoma, is contagious. It is spread by tumor cells getting passed from dog to dog through sex or from animals biting or licking each other. Robin Weiss and his colleagues did genetic studies on the tumor cells from 40 dogs with Sticker's sarcoma, collected from five continents, which showed that all the tumor cells are clones of each other. The parent cell probably arose in a domesticated dog of Asian origin — perhaps a husky — hundreds of years ago, and perhaps more than 1,000 years ago. A similarly transmissible cancer has recently been discovered spreading through populations of Tasmanian devils."

Comments

Transmitted through sex?

[ArcherB]

Great! Now I have to give my dogs a talking-to about using protection before they go to the doggie park!

I wonder if they will start having puppy prophylactics in a candy dish at pet-smart.

Re:Transmitted through sex?

[MustardMan]

Man, am I glad I had my dog's balls chopped off. Nearly all of his humping instinct is now gone... we might have dodged a bullet!

Re:Transmitted through sex?

[Rude Turnip]

My two dogs are without C.A. Jones and are still at it now and then.

Re:Transmitted through sex?

[krawz]

Hopefully the people at PetSmart will handle the...application...of the aforementioned 'protection', because I know I'm not. Imagine the Want Ad... PetSmart, Inc is now seeking a full-time Canine Fornication Specialist. 1+ year(s) previous CFS experience preferred. Dust off your rubber glove and drop off your application today!

Re:Transmitted through sex?

[beadfulthings]

Your image is so funny I hate to get all serious on you. But this seems like a pretty good spot to inject a word about spaying/neutering. In addition to not adding any more unwanted puppies to the 6 million or so we already have in the US, now we can say we're providing Fido with the ultimate in protection against doggie STD's.

Re:Transmitted through sex?

[oahazmatt]

I wonder if they will start having puppy prophylactics in a candy dish at pet-smart.

Christ, it's hard enough to get them to take their vitamins. Putting one of those on 'em is gonna be a pain.

"Hold on, boy, there's an air bubble."

Re:Transmitted through sex?

[gstoddart]

Christ, it's hard enough to get them to take their vitamins. Putting one of those on 'em is gonna be a pain.

"Hold on, boy, there's an air bubble."

Well, by the time you work out the air-bubble, he might just want a smoke and a cuddle. Then you won't have to worry about him humping strange dogs. :-P

Cheers

Re:Transmitted through sex?

[jez9999]

This almost looks like a parody.

URGENT: PRODUCT RECALL:
"FOR IMMEDIATE RELEASE -- Bloomington, IN - August 3, 2005 -- Dog Condoms, Inc.
is announcing a voluntary recall of its Dog Condoms® canine prophylactics, due
to an unacceptable failure rate reported during preliminary release in test
markets."

No shit, they couldn't permenantly monitor their dog and slip this on just before penetration.

It happens in humans, too.

[Skynet]

http://en.wikipedia.org/wiki/HPV#Cancer

Make sure to use protection, Slashdotters!

oh wait....

Re:It happens in humans, too.

[thebdj]

There is a big difference. In the HPV case, there is a viral infection THAT MAY cause cancer in people with the virus. This is talking about the tumor cells actually transferring from one animal to another to cause infection. So to recap, HPV is a virus that may cause cancer in women with it and should not be confused with communicable cancer. A communicable cancer would be transferred from person one to person two and cause a cancer infection. (You know, how the flu, common cold, and a host of other diseases work.)

Re:It happens in humans, too.

[Anonymous Coward]

If you had RTFA :

Cancer-causing viruses may spread from person to person, but the cancer does not. But the dog cancer, known as Sticker's sarcoma, is spread by tumor cells getting passed from dog to dog through sex or from animals biting or licking each other.

Re:It happens in humans, too.

[Burlap]

close, but not quite.

Human Papolova Virus (HPV) can be transmitted from person to person, however the cancer cells it creates are from the host. The article states that in this case the very cancer cells themselves are being transmitted and growing in a new host. These tumors have no genitic relation to host, whereas HPV induced cancers do.

Re:It happens in humans, too.

[Skynet]

Very true, thanks for pointing that out.

Although at a primitive level, you are getting cancer as a direct result of sexual contact with another person.

Re:It happens in humans, too.

[eli pabst]

I haven't read the journal article in Cell yet, but from my understanding this isn't interesting from the standpoint of a virus being able to transform normal cells into a tumor. There are a large number of examples of that (EBV, KSHV, hepatitis B virus). This is interesting because it's the actual tumor cells themselves that are being transmitted from one host to another. You can do that in the lab by injecting tumor cells from one mouse into another and letting a new tumor form, however I haven't seen examples of this occuring naturally and in those experiments the mice need to either be from the same genetic background or immunosuppressed SCID mice.

Re:It happens in humans, too.

[Skynet]

I, indeed, did not RTFA closely enough apparently. :)

Re:It happens in humans, too.

[Raindance]

Carl Zimmer has a great post on this:

http://scienceblogs.com/loom/2006/08/09/an_old_dog _lives_on_inside_new.php

FTP:
"The scientists propose that several centuries ago, a histiocyte cell in a dog or a wolf turned cancerous. A mutation may have caused the cell to become abnormal--perhaps that LINE-1 element that marks Sticker's sarcoma cells today. But natural selection would have favored other mutations as well that allowed its descendants to become more effective at growing into a tumor. During mating, some of the cancer cells managed to spread to the dog's partner, where they could continue to proliferate."

It's pretty freaky that some ancient dog has essentially turned into a contagious cancer. Not the fate I'd choose...

Re:It happens in humans, too.

[Hal_Porter]

It reminds of the Doctor Who episode "Tooth and claw"

http://en.wikipedia.org/wiki/Tooth_and_Claw_(Docto r_Who)

It'd be pretty cool if you could bring your consciousness along in the contagious cancer cells like the wolf did, not that I can think of how this could possibly work.

Re:It happens in humans, too.

[gardyloo]

Make sure to use protection, Slashdotters!

oh wait....

    Yes, I think you caught the redundancy inherent in that statement, didn't you?

Re:It happens in humans, too.

[thebdj]

There is a HUGE difference. People with certain types of HPV may or may not get cancer. It is not a given. You are right to some degree in that the important thing is they have found A cancer that is contagious. Don't say all cancer is contagious that is for the sensationalist media to provide.

Re:It happens in humans, too.

[Afrosheen]

Better late than never huh? ;)

Re:It happens in humans, too.

[RDW]

'You can do that in the lab by injecting tumor cells from one mouse into another and letting a new tumor form, however I haven't seen examples of this occuring naturally and in those experiments the mice need to either be from the same genetic background or immunosuppressed SCID mice.'

I didn't know this either, but according to the article: "CTVT was frequently used by cancer researchers to study tumor transplantation" (presumably in dogs) "until the development of inbred strains of rats and mice afforded syngeneic models" while "CTVT can be transplanted into immunocompetent animals of other canine species, such as foxes, coyotes, and jackals...as well as into immunodeficient mice" (but presumably not immunocompetent mice). Interestingly, the typical course of the disease in dogs is "an initial stage of rapid and progressive growth, which is typically followed by spontaneous regression 3 to 9 months later", so the animal eventually mounts an effective immune response (passive immunity can also be transmitted by serum from a recovered dog).

Re:It happens in humans, too.

[santiago]

No, the fact these are infectious cells and not cancer-inducing viruses is precisely why this is important. It's like the distinction between viral and bacterial infections. They're completely different.

Re:It happens in humans, too.

[tieTYT]

Why doesn't dog two's immune system identify that there is a foreign body (a cell from dog one) and destroy it?

Re:It happens in humans, too.

[Reziac]

The immune response is interesting... I've observed an apparently contact-contagious tumour in dogs, and have also noticed that these tumours tend to be self-limiting or sometimes even regress.

[Side note: I am a professional dog trainer.]

Re:It happens in humans, too.

[Jorgandar]

I find it sad that this has to be explained. What kind of idiot cant seem to figure out the difference between a communicable cancer and a communical virus that causes cancer. Do your f*ing homework people.

Re:It happens in humans, too.

[mambodeath]

I don't think the method of communicability being slightly different is what is important here. The reason this is being reported is that the cancer is contagious. And that is what is important.

but we've known from animal experiments since at least the 1960's that (i)cancer has a viral component and (ii)tumors from a cancerous animal injected into a healthy animal cause cancer. we've also known that the virus associated with many soft tissue cancers is transmitted sexually as well as from mother to offspring.

cdc records as well as this book http://www.themonkeyvirus.com/ have more info.

Re:It happens in humans, too.

[mpe]

This is interesting because it's the actual tumor cells themselves that are being transmitted from one host to another. You can do that in the lab by injecting tumor cells from one mouse into another and letting a new tumor form, however I haven't seen examples of this occuring naturally and in those experiments the mice need to either be from the same genetic background or immunosuppressed SCID mice.

Mice bred for laboratory use specifically are intended to have minimal genetic diversity within a specific strain. Whereas this is not the case with domestic dogs as a species.

Re:It happens in humans, too.

[mpe]

Why doesn't dog two's immune system identify that there is a foreign body (a cell from dog one) and destroy it?

That being the mystery. There is something unusual about these cells. Another thing is that the normal immune can take place, but after a tumour has been allowed to develop over several months.

The Punnic Wars, Part 2

[krell]

"We had a chance with aids, but we blew it."

You can say that again.

Re:The Punnic Wars, Part 2

[Hal_Porter]

Maybe you should start a group to campaign against Fascismophobia.

It's just a new form of racism!!!11!

Re:The Punnic Wars, Part 2

[Eideewt]

I thought to myself, "Surely this article mentioned that it's generally not a fatal disease." So I took the time to RTFA, and sure enough, it did say that. Perhaps you would have been less worried if you had taken the time to read to the fifth paragraph.

Timmy Didn't Kill Old Yeller

[Anonymous Coward]

The parent cell probably arose in a domesticated dog of Asian origin -- perhaps a husky -- hundreds of years ago, and perhaps more than 1,000 years ago.

Tonight, President Bush will go on TV and address the nation saying that recent research has shown that China & North Korea used biological weapons on the United States and its best friends. This will be justification for the preemptive nuclear attacks the United States has planned next week. He's got a real good feeling about this one. It's a slam dunk.

Re:Timmy Didn't Kill Old Yeller

[w0d3h0us3]

On what planet is this sort of nonsense "Insightful"?

Re:Timmy Didn't Kill Old Yeller

[stunt_penguin]

A funny one.

Re:Timmy Didn't Kill Old Yeller

[Yvanhoe]

"The Korean Dog Sex Weapon"

Now I see the headlines...

Re:Timmy Didn't Kill Old Yeller

[kalirion]

Not even Bush is a great enough moron to attack a nuclear power. And even if he was, I doubt Dick Cheney and the cabinet and the Pentagon are all suicidal enough to let it happen.

tasmanian devil & spreading cancer

[fredouil]

unfortunately this kind of cancer is not new, here in Australia, the Tasmanian devil are diying and will soon disapear. http://news.nationalgeographic.com/news/2006/02/02 27_060227_tasmanian.html

Re:tasmanian devil & spreading cancer

[GweeDo]

But who will eat all the pizza rolls?

Re:tasmanian devil & spreading cancer

[PRMan]

But wouldn't this just result in the more tame (less prone to bite) devils surviving? Isn't that how evolution works?

Re:tasmanian devil & spreading cancer

[Qzukk]

I suspect the more-tame ones would be killed off by the more-vicious ones before the more-vicious ones themselves die.

Re:tasmanian devil & spreading cancer

[krakelohm]

I don't think so. I would think you need more time (generations) to change their behavior.

Re:tasmanian devil & spreading cancer

[slamb]

fredouil writes:

unfortunately this kind of cancer is not new, here in Australia, the Tasmanian devil are diying and will soon disapear. http://news.nationalgeographic.com/news/2006/02/02 27_060227_tasmanian.html

Here's a question: is it right for us to stop it? This appears to be a natural weakness of Tasmanian devils. The article states:

Pearse noted that inbreeding, and the resulting lack of genetic diversity, may make Tasmanian devils particularly susceptible to this type of infection.

and so an unsuccessful species is dying out, as has happened many times in the past. Now humans are around to stop it (the government is quarantining them; there's even talk of cloning, should the entire population die), but is it beneficial to tamper with nature in this way?

Re:tasmanian devil & spreading cancer

[Anonymous Coward]

Here's a question: is it right for us to stop it? This appears to be a natural weakness of Tasmanian devils.

Humans aren't above evolution. We're part of the process. And one thing evolution has given some of our species is empathy. Another is to determine a system of values to live our lives by. If enough of us determine that the "right thing to do" is to save the Tassie Devil because we're concerned about their plight, then evolution has seen fit to give the Tassie Devil a leg up. There's no right or wrong, just an outcome.

Re:tasmanian devil & spreading cancer

[RsG]

I dislike the arguement that "nature" has any intent or say in the matter. It's too close to a religious belief for my liking; making the natural world or the proccess of evolution into some planning, thinking deity.

Evolution is non-linear. It's a blind proccess based on probability, not some infallable mechanism for ensuring the correct changes occur. Extinction is not fated, nor does it unerringly take only those species who are unsuited to their environment (look at the major mass extinctions in history as proof of this).

And even when natural selection is responsible, why is that "right"? Evolution has no ethics, it simply is. Moreover, even if we start from the assumption that natural selection is right (or is best not interfered with), how can we seperate it out from every other factor involved in an extinction? Death by evolution is like death from old age; it's not a specific cause, it's a general description of what went wrong.

The death of the dodo or the passanger pigeon can argueably be considered a form of evolution; those species unable to cope with a new predator (man) die off. Yet we restrain ourselves from causing other species to go extinct.

We are ourselves unnatural creatures. The natural state of humans is poor health, early death, superstitious ignorance and starvation. We're hunter-gatherers naturally. Do we view our deviation from evolution as wrong?

And even if the tasmanian devils are dying out purely due to non-human factors, what arguement is there against trying to preserve them?

If you want to argue that the only species we have an obligation to preserve are the ones that our own actions have endangered, then that's fine - you're entitled to your own point of view. However, I don't agree with that line of thinking. The fact that we're probably blameless in the fate of the tasmanian devil doesn't mean we have no cause to preserve them.

Re:tasmanian devil & spreading cancer

[Rakishi]

My general statement to such people who claim "nature meant it" is for them to go play Russian roulette with a half loaded gun. That will simulate how much nature meant for them to survive had it not been for all the nice inventions we humans made.

Re:tasmanian devil & spreading cancer

[landryraccoon]

A good attempt, but you started contradicting yourself too early in the post.

And even when natural selection is responsible, why is that "right"? Evolution has no ethics, it simply is. Moreover, even if we start from the assumption that natural selection is right (or is best not interfered with), how can we seperate it out from every other factor involved in an extinction? Death by evolution is like death from old age; it's not a specific cause, it's a general description of what went wrong.

Nothing can ever go wrong if your paradigm is evolution through random natural selection. Things just die. There is nothing ever wrong or unnatural about this, whether a human being was involved or not.

We are ourselves unnatural creatures. The natural state of humans is poor health, early death, superstitious ignorance and starvation. We're hunter-gatherers naturally. Do we view our deviation from evolution as wrong?

Two mistakes. One, human beings can't be unnatural, nor can our activities be unnatural. That would imply the possibilty of a non-natural cause or factor involved, which you already said can't exist. Pumping petroleum out of the ground, killing each other with cruise missiles and causing mass extinctions are all completely natural, the consequence of random evolution and all within the understood laws of physics. Thus, nothing we do can be wrong, nor can it be unnatural. Under an evolutionary paradigm, how can the natural state of human beings (or anything else, for that matter) be anything else than what it is? Secondly, by definition, a human being can't deviate from evolution, becuase again, that would imply a non-naturalistic cause or involvement, which can't exist. Everything we do is part of the natural course of our evolution. Finally, if there WERE some way to deviate from evolution, there is certainly no way it could be described as "wrong", except under some sort of arbitrary cultural and human constructed ethical viewpoint.

And even if the tasmanian devils are dying out purely due to non-human factors, what arguement is there against trying to preserve them?

There are plenty of arguments on both sides, I'm sure, but as far as evolution is concerned, there is no argument for or against preserving them.

If you want to argue that the only species we have an obligation to preserve are the ones that our own actions have endangered, then that's fine - you're entitled to your own point of view. However, I don't agree with that line of thinking. The fact that we're probably blameless in the fate of the tasmanian devil doesn't mean we have no cause to preserve them.

Ok, now you've totally lost it. Species can't possibly have any obligations under evolution. You survive and reproduce, or you don't. Do tasmanian devils help us survive and reproduce? Maybe. Do we have an obligation to the tasmanian devil, or any other species? Maybe. But I don't see how. I assume that to continue arguing in favor of saving species, you would have to appeal to some sort of religious entity, or an arbitrary and culturally constructed ethic which uses words like "right", "wrong", and "should"?

Re:tasmanian devil & spreading cancer

[exp(pi*sqrt(163))]

It's a blind proccess based on probability, not some infallable mechanism for ensuring the correct changes occur.

The two are not mutually incompatible. That two containers of gas equalise pressure when connected is also a blind process based on probability. And yet the outcome is almost inevitable. There are non-trivial things we can say about evolution by natural selection despite it being a random process.

Re:tasmanian devil & spreading cancer

[RsG]

Yet, to use your own example of pressure change, we can make no statement about the movement of a single molecule of gas. We can only state what the preponderance of gas molecules will do; gas law is accurate in the aggregate.

What I have a problem with is the idea that evolution (or nature) does anything as if governed by intelligence. This is a widespread misconception, based on a sort of anthropomorphicised concept of natural proccesses. There is no more intent to evolution than there is to the movement of molecules in a gas container, yet both proccesses behave predicably. This predicability fools people into thinking there is more going on than probability.

When someone says that a species is not "meant" to survive (as the person I initially replied to did), what they're doing is assuming intent on the part of evolution. Hence my reply disputing this. Perhaps I should have been clearer.

Re:tasmanian devil & spreading cancer

[RsG]

First off, it would probably have been better had I made it clear what I was arguing against. The GP (the person I replied to initially) was ascribing intent to nature, as if the proccess of evolution was somehow intelligent. Ergo, comments about right/wrong have more bearing on the idea that there is a "goal" to evolution, or an objective way to measure evolutionary fitness. I take issue with this idea; I don't like it when people make evolution or "nature" out to be some sort of thinking being.

I mention this because you seem to have taken some of my post out of context. That being said...

Two mistakes. One, human beings can't be unnatural, nor can our activities be unnatural. That would imply the possibilty of a non-natural cause or factor involved, which you already said can't exist.

Unnatural in this context was taken to mean "no longer governed by evolution". Natural selection gave us intelligence, but how we use that intelligence has very little bearing on what its original function was.

You could argue that we evolved as toolmakers and social animals, and that therefor anything arising out of technology or society is inherently natural to human beings. I'd rather not get into this however, as I've had that debate before and find it too easy to get bogged down in semantics. In the context of my post, I was using "natural" in the same manner as the person I replied to.

Everything we do is part of the natural course of our evolution. Finally, if there WERE some way to deviate from evolution, there is certainly no way it could be described as "wrong", except under some sort of arbitrary cultural and human constructed ethical viewpoint.

Since we're debating the intervention of humans into the survival of another species (tasmanian devils), that "arbitrary cultural/ethical viewpoint" is crucial. I hardly think you can somehow seperate human motivations in this sort of situation from our culture.

If we're debating whether it is right to intervene in the natural extinction of a species, then what we're debating is ethics. Ergo, "wrong" does have a meaning. If we choose to view interfering in natural selection as ethically wrong (as the GP seems to think), then what does that say about our own development, where we've done exactly that to ourselves?

There are plenty of arguments on both sides, I'm sure, but as far as evolution is concerned, there is no argument for or against preserving them.

Agreed. And my only point there was that the GP was trying to use evolution as an arguement against presevering them; I do not think that evolution is a factor either for or against.

Ok, now you've totally lost it. Species can't possibly have any obligations under evolution

Do you use evolution as your measure or right or wrong in your own life?

I ask this because most of what I wrote was on either the idea that evolution isn't a system of morals (which we seem to agree on), and that we shouldn't feel obligated to stand aside and allow natural selection to make a species extinct. I don't recall saying we had an obligation to preseve them; I said we could choose to, and should not adopt a non-interference policy.

Re:tasmanian devil & spreading cancer

[nukeade]

Wikipedia claims that partially resistant females have been found in the wild.

It seems like the Tasmanaian Devil population may be large enough and that this cancer will provide sufficient stress on the population (unlike the relatively benign dog version) that the devils will evolve an immunity. Look at the dog version. It's been around for thousands of years precisely because it's not particularly lethal. It's no surprise that these types of cancer seem to be so rare--the most dangerous ones were relatively quickly cured in healthy populations through evolution.

~Ben

Re:tasmanian devil & spreading cancer

[stonecypher]

Way to repeat the last sentence of the article.

Re:tasmanian devil & spreading cancer

[exp(pi*sqrt(163))]

When someone says that a species is not "meant" to survive (as the person I initially replied to did), what they're doing is assuming intent on the part of evolution

This is nothing other than the naturalistic fallacy. Nature doesn't 'mean' anything.

But I've nothing against anthropomorphization if you are aware of what you are doing. I find it quite useful to treat nature as if it has 'intent' because I can make predictions based on it. For example, if I buy a machine and see it has a complex piece of engineering within it it's probably reasonable to assume that this piece of engineering serves a purpose because it would be weird for a designer to put all that effort into designing something useless. I can use similar forms of reasoning if I find a bizarre but complex organ within an organism that I don't understand. Despite my lack of understanding it's still reasonable for me to think "nature wouldn't create something like this without a purpose". In fact, almost every discovery of an apparently useless organ has eventually led to a discovery of its purpose, so this form of reasoning is valid. Hence I use intentional language when discussing evolution by natural selection.

Nonetheless, I'd still never say "this creature is not meant to survive". That's not a prediction of anything. It's just a value judgement.

Re:tasmanian devil & spreading cancer

[LukeWebber]

Nope. There are no tame devils. They're all mean little suckers. And if there were, they'd be bitten to death before they could die of cancer.

Re:tasmanian devil & spreading cancer

[deuterium]

There's no right or wrong, just an outcome.

Ahh... a coward after my own heart. I've labored on many occasions to illustrate the fact that whatever people do, it is literally natural. To assume anything else would be placing us in the realm of (again, literally) the supernatural. So whether we destroy the planet, live in wigwams, colonize Mars, or genetically engineer a mouse that glows in the dark, the result is no more unnatural than a beaver damming up a culvert. There is no grand evolultionary, Gaia-mind plan that we run the risk of mucking up. The laws of nature simply play themselves out wordlessly and aimlessly. Isn't that comforting?

Re:tasmanian devil & spreading cancer

[localman]

I thought it was 'kinky' when you 'use the whole chicken'? Exotic just doesn't sound right.

Re:tasmanian devil & spreading cancer

[monoqlith]

Yes, but in all of those cases you use the word 'intent' loosely, because as you say the concept of intent helps you to understand why there are prevalances of one trait over another. As such, all you are really saying is that the world follows laws that are predictable. You don't mean literal intent - evolution is not some teleological race to the finish line, intelligence. Any teleological view of evolution is an loose interpretation not based on the objective reality. Evolution is so natural as to be completely untainted by human constructions such as 'purpose', 'intent', 'utility.' When we assign purposes, utilities, or values to objects we are creating them out of thin air, or we are inheriting them from someone else - in which case we are also creating them out of language or concepts. Purpose is an invention. There are no preceding qualities or values for each object, there is nothing in them that tells us "This is what I am to be used for." All of these concepts are prescribed by the human mind and are used to impose on objects the character of a function.

Re:tasmanian devil & spreading cancer

[jez9999]

The natural state of humans is poor health, early death, superstitious ignorance and starvation. We're hunter-gatherers naturally. Do we view our deviation from evolution as wrong?

What on earth are you talking about? The 'natural' state of humans in the West is generall good health, late (and getting later) death, and a full belly. Superstitious ignorance, whilst widespread, is neither a physiological thing (which evolution tends to deal with) nor anywhere near ubiquitous.

Unless you mean 'natural state' to be the state you're in if you do nothing and get no food, but that's a pretty dumb thing to look at; any animal would be buggered if they got no food and did nothing for a long time.

Re:tasmanian devil & spreading cancer

[RsG]

Natural state in this context means the state that evolution prepared us for. We didn't evolve brains in order to post witty comebacks on slashdot, we evolved them to survive as hunter gatherers. Tool making functioned as a way to kill food, not play with computers.

The normal state of people living in an industrial society has zero bearing on the conditions we evolved under. Evolution takes millenia, while technological advances take decades, if that. The life we evolved for is ancient history, yet our natural instincts are still geared for it (try applying your fight or flight reflex the next time you get a speeding ticket).

My primary point was that what was natural from an evolutionary perspective has no bearing on the modern human world. If we equate "unnatural" with "wrong", then aren't we condeming ourselves? I don't think so, but the GP seemed to, hence my arguement.

Re:tasmanian devil & spreading cancer

[bettlebrox]

>and so an unsuccessful species is dying out, as has happened many times in the past. I was under the impression that the reason for the weak gene pool was because of over-hunting by humans.

Re:tasmanian devil & spreading cancer

[shawb]

If you want to argue that the only species we have an obligation to preserve are the ones that our own actions have endangered, then that's fine - you're entitled to your own point of view. However, I don't agree with that line of thinking. The fact that we're probably blameless in the fate of the tasmanian devil doesn't mean we have no cause to preserve them.

And even if you take it a step further and argue that humanity is the only species we have an obligation to preserve, it can still be argued that it is in our best interest to attempt to preserve the tasmanian devil. 1)It is only logical that allowing all other organisms to die out will eventually mean that some organism we rely on for survival (if not as a species, then at least as a society) will die out. 2)Studying the plight of the Tasmanian Devil may give us insights into biology that will aid the medical field as applied to humans if such a phenomenon were to cross over or spontaneously arise in humans.

I suppose the real question would be how much of our resources should we expend in attempting to save the Tasmanian Devil (or any other species in a similar situation.) I can't picture any person saying that every person on the earth should devote all their time, money and property to ensuring the survival of the Tasmanian Devil, even if it is found that humanity was indeed responsible for their plight (population bottleneck due to territory loss to human development leading to a lack of population resistance to transmissable cancers? The cancer was originally sparked by man-made pathogens? Escape of a laboratory research project into the wild? All plausable, off the cuff possibilities.) On the other hand, their plight does merit at the very least basic research, at least standard tracking of population dynamics so we can build finer models of disease transmission and resistance (assuming that this is not extremely resource intense) so it can at least be said that the species did not die out in vain.

Re:tasmanian devil & spreading cancer

[binarybum]

Rednecks everywhere just shed a tear.

Re:tasmanian devil & spreading cancer

[rarkm]

"In this best of all possible worlds, all things are for the best" CANDIDE, Voltaire

How are these Cancer Cells?

[mochan_s]

It is spread by tumor cells getting passed from dog to dog through sex or from animals biting or licking each other. Robin Weiss and his colleagues did genetic studies on the tumor cells from 40 dogs with Sticker's sarcoma, collected from five continents, which showed that all the tumor cells are clones of each other.

So, all tumor cells are clones of each other and not related to the dog. How is this cancer? Isn't it just a regular pathogen then?

Re:How are these Cancer Cells?

[ComaVN]

Regular pathogens did not originate as animal cells

Re:How are these Cancer Cells?

[6OOOOO]

Not a doctor, but...

Presumably the oddity is that it's a cancer that behaves as a pathogen--that is, these are rogue dog cells that can jump from dog to dog and continue reproducing as a tumor. It's closest, really, to a parasite, but it's still weirder than that, since it's genetically the same species as its host.

Re:How are these Cancer Cells?

[LurkerXXX]

It's a parasite. The strange thing is their claim that after dog bites these "cancer cells clog up the jaw, and the poor animals die of starvation".

I can see how a parasite like this might get a free ride in the genital tract, but in the case if bites like this, the host dog's immune system should recognize these 'cancer' cells as foreign material and destroy them.

Re:How are these Cancer Cells?

[Randolpho]

That's a very interesting point. How do you label this? It's not a virus, or it would infect healthy cells of the host. It doesn't appear to be bacterial. It's not really a cancer, since cancer is a part of the host's own cells. What is it?

It *behaves* most like a bacterial infection, but it causes tumors. Or rather, it pauses in a host and somehow replicates itself in large quantities, which is mistaken for a cancerous tumor. How does it feed?

This is a very interesting biological concept.

Re:How are these Cancer Cells?

[rabbitfood]

They are related to the dog simply because they are dog cells (and most dogs are genetically very similar), they just happen to be cancerous, transmissible and genetically identical dog cells. Tumour cells are usually aberrant (mutant) cells from the host animal that don't differentiate (i.e. turn into the right sort of cells for the tissue they are in) and don't regulate their division (i.e. they multiply without restraint). That's what makes them cancerous. And because most of them don't look anything special to the immune system, they don't get rejected.

Contagious cancers aren't a new idea, but the transmission methods aren't very clear. This research clarifies an important element of the process that will be useful in defining healthcare strategies for both animals and humans. Happily, health organizations are well used to managing such threats, and once sex has joined smoking as an unacceptable activity, we'll wonder what all the fuss was about.

Re:How are these Cancer Cells?

[Lazbien]

It's not a tumor...

Re:How are these Cancer Cells?

[Red Flayer]

FTFA:

"I rather thought we might disprove this, but it came out the other way around," said Robin Weiss, of University College London, who led the study appearing in today's issue of the journal Cell. "It is clearly a dog tumor cell behaving absolutely like a parasite." Weiss called the tumor transmission trick "a curiosity of nature."

This isn't the first time that a communicable parasite has evolved from a host's own cells and/or cell contents. Prions, such as the ones thought to cause BSE, are another intesting example, possible even harder to classify -- enough so that they've been given their own classification.

I would think that though the diseases from TFA originated as cancers, they now behave like parasites, and should either be labeled as such or given a new designation all their own.

Re:How are these Cancer Cells?

[MS-06FZ]

Not a doctor, but...

No no no... you got it all wrong.. The line is:

"Damnit, Jim, I'm a doctor, not..."

Re:How are these Cancer Cells?

[mrchaotica]

How does it feed?

Probably the same way as any "normal" cancer: it gets supplied with nutrients and oxygen from the blood stream, just like all the rest of the dog's cells.

Re:How are these Cancer Cells?

[Graff]

The strange thing is their claim that after dog bites these "cancer cells clog up the jaw, and the poor animals die of starvation".

That's the cancer that affects tasmanian devils, not not the cancer that is affecting dogs. The dog version apparently is very rarely fatal to the dogs that contract it.

Re:How are these Cancer Cells?

[NearlyHeadless]

It's closest, really, to a parasite, but it's still weirder than that, since it's genetically the same species as its host.

It's genetically almost identical, but I think we can say this is a new species. It's thus a single-cell species of dog.

Re:How are these Cancer Cells?

[Kymermosst]

My I be the first to name it "oncoperegrine disease".

Re:How are these Cancer Cells?

[Red Flayer]

Cancer-hawk disease? Sweet. How about "Oncoraptors"?

Yeah, I know you mean peregrine as in ambulatory. How about heterometastasizing oncocytes? Then we could call HMOs a type of cancer for real.

Re:How are these Cancer Cells?

[TheRaven64]

It's the same species as a dog if it can mate with a dog and produce fertile offspring. Considering how it reproduces, I'm not quite sure if this is happening or not.

Re:How are these Cancer Cells?

[Alsee]

It's genetically almost identical, but I think we can say this is a new species. It's thus a single-cell species of dog.

LIE! There's no such thing as a "new species"!

Remember kids, the Bible is a literally true history and science text book, the earth is 6000 years old, evolution is a liberal left wing lie to wipe out God, and Noah carried two cells of this species of Dog on the Arc.

-

Re:How are these Cancer Cells?

[Reziac]

Great, and here I thought the toy breeds were already too damn small ;)

Re:How are these Cancer Cells?

[stonecypher]

This might be the single funniest thing I've read on Slashdot all year.

Re:How are these Cancer Cells?

[SEE]

Hmm. It's a case of a specific dog (the one in which this originated as a cancer) having mutated/evolved into a unicellular eukaryotic parasite that's hosted by canines, which as a symptom of initial infection forms an almost-benign, short-lived tumor (the immune response in most dogs causes the tumors to go into spontaneous remission, apparently).

Re:How are these Cancer Cells?

[xilmaril]

Evolutionary Biologists aren't actually certain of this. For example, they still aren't quite sure how viruses came to be. One heory is that they came from cellular RNA. Anyone familiar with the subject beyond the scope of a biology 12 class, feel free to confirm/correct this.

Re:How are these Cancer Cells?

[mpe]

Or let's turn this on its head. You can breed a kingsnake with a cornsnake (separate genuses, let alone species) and get fertile offspring. Does that mean they're the same species?

Many classifications were originally based on phenotype. If you went only by phenotype you might well classify a Great Dane and a Chuaua as being from different species.

Re:How are these Cancer Cells?

[Alsee]

You and I agree that "radical fundamentalist Christian crackpot" should not be assumed to equal "all of Christianity", just as "fundamentalist suicide bombers" should never be accepted as equating to "all of Islam". Radical fundamentalists of all brands try to push that assumed equality. People all too often implicitly buy into that equating, both inside that religion and outside it.

I don't mean this as an attack, but I think it's you who implicitly bought into that assumption a bit. That that is the reason you felt that an attack on them = an attack on you.

-

Re:How are these Cancer Cells?

[plunge]

You are correct, at least insofar as this is one speculation. There are any number of such sub-cellular "thingies." Prions are another example: according to our theory of how they work, they are botched proteins that make other proteins get botched in the same way (leading to things like mad cow disease and the horrible deadly insomnia that one family evolved).

However, these cancers aren't really like viruses: where a bit of code branches out on its own. These cells really are in a sense, dog cells that have acquired the new ability to act like a pathogen. It's evolution on a new scale, where heredity in terms of genetics is similar (a mutation, but in this case a non-germ-line mutation) that is preserved, but the heredity in terms of morphology is radically different (first these cells were parts of a "dog" and now they are individual agents that live IN dogs, despite being genetically dog!)

Re:How are these Cancer Cells?

[plunge]

The bottom line is that evolution fucks up any nice neat concept of species. We can mate llamas with camels. We can mate dolphins with false killer whales. Heck, we don't even know for sure that humans cannot breed with chimps: it's just that we haven't really tried as hard as we did with other species and aren't likely to try. There is no nice neat continuum of when or how one species stops being able to produce fertile hybrid offspring, nor is there any one easy definition of species as a result.

Re:How are these Cancer Cells?

[mpe]

Heck, we don't even know for sure that humans cannot breed with chimps: it's just that we haven't really tried as hard as we did with other species and aren't likely to try.

There's always Human/Bonobo given that Bonobos are genetically closer to humans than chimps.

Not Taz!!

[Rob T Firefly]

A similarly transmissible cancer has recently been discovered spreading through populations of Tasmanian devils.

Symptoms include dizziness, slurred speech, and violence toward woodland creatures... especially rabbits.

Your dog wants a condom

[mobby_6kl]

getting passed from dog to dog through sex ... or licking each other.

And it doesn't seem that human to human cancer transmission is impossible, too. This could be the next big thing once we've cured AIDS.

How common is Sticker's sarcoma, though? We have a dog, and although she's not getting to fuck like a rabbit, dogs often lick each other and sometimes bite.

Re:Your dog wants a condom

[JoshDM]

How common is Sticker's sarcoma, though? We have a dog, and although she's not getting to fuck like a rabbit, dogs often lick each other and sometimes bite..

See this post.

Damn...I just lost my dog to cancer.

[ip_freely_2000]

A 9 year old Border Collie with an aggressive tumor in her front leg. This happened two weeks ago. She spent a lot of time playing with other dogs in the park. I'd hate to think that me wanting my dog to have some fun is what killed her. I'd hate to have to wonder and worry about this with my next dog.

Re:Damn...I just lost my dog to cancer.

[SlashSquatch]

Condolences.

About the bark park, your dog would not have had it any other way.

Don't worry because:

1. Even though you may point to a risky behavior, this does not imply a cause - effect relationship. Many cancer causing agents will always abound in our environment.

2. I'd choose bark park with a 3/4 life span vs. no fun for a long time and all the other dogs I know agree.

3. A good chunk of the dog population gets the shaft, stuck on a chain, or in a cage and possibly gassed in their prime.

Re:Damn...I just lost my dog to cancer.

[Like2Byte]

The key, I've found, is to enjoy the company of what ever animal or person you love while they are still with us. Some things we can't control. Life happens and part of life is death. Take lots of pictures and enjoy the time you've been given. Lamenting what could have been produces only poisoness fruit for the soul and the mind.

Love. In the end, it's all you can do to honor someone close to you.

Re:Damn...I just lost my dog to cancer.

[Anonymous Coward]

Probably not the cause. From the article: "Sticker's sarcoma is usually not fatal . . .".

Re:Damn...I just lost my dog to cancer.

[Johnny5000]

A 9 year old Border Collie with an aggressive tumor in her front leg. This happened two weeks ago. She spent a lot of time playing with other dogs in the park. I'd hate to think that me wanting my dog to have some fun is what killed her. I'd hate to have to wonder and worry about this with my next dog.

Sorry to hear about your dog.
As much as it sucks to lose a pet, I'm sure she would have preferred a shorter, fun and happy life to being bored and cooped up inside all day.
Besides, there's no indication that it was the playing with other dogs that caused her tumor, so no need to blame yourself for that.

Re:Damn...I just lost my dog to cancer.

[Reziac]

Firstoff, I'm a pro dog trainer/breeder with 37 years and some 1800 dogs worth of experience.

I've seen about a dozen cases of what I suspect is a contact-contagious cancer in dogs, but the tumours produced are limited to skin and fat, are not aggressive or progressive (in fact are generally self-limiting), and are never fatal.

What you describe, given the not-so-old age of your dog, was probably inherited, and secondary to immuno-deficiency (which does occur in Border Collies). There's nothing you can do about that; it's just bad luck.

Most canine cancers that are not due to the systemic failings of late old age, are in fact
familial, and in-depth pedigree histories (including all siblings and cousins) will demonstrate that. (Pedigree analysis wrt tracing defects is one of my specialties.)

So.. it's nothing you did or didn't do, and don't let it stop you from enjoying your next dog to the fullest.

Re:Damn...I just lost my dog to cancer.

[RockModeNick]

The tumors mentioned in the article appear to cause only growths under the skin, nothing fatal, so I don't think you should have to feel bad. Try reading some earlier comments, and condolences on your loss, I always take a dying pet very hard.

Wait, I saw this movie...

[Phoenixhunter]

I believe it was John Carpenter's masterpiece, The Thing. Dog eats alien, dog transforms into bloated mass of cells, Thing eats humans.

Re:Wait, I saw this movie...

[fullphaser]

no I think you are thinking of Aliens 3, dog finds alien, alien eats/fuses with/uses dog, alien/dog hybrid goes on killing spree

Re:Wait, I saw this movie...

[Ana10g]

Not sure about alien 3 (it's been a long while since I've seen it), but the thing is spot on... http://www.imdb.com/title/tt0084787/

Re:Wait, I saw this movie...

[xlordtyrantx]

In Alien 3 the dog was infested by the alien parasite, just like the people were in all the other Alien movies. Those took on a humanoid apearance, while the alien that infested the dog took on a more dog-like apearance (if you can call it that). In the Thing, the dog just ate it ... No relevance to the topic, just clearing up the other post ;-)

Cancer clusters...

[Varka]

Perhaps this will turn out to be a partial explanation for the "cancer clusters" you read about every now and then. Varka

Re:Cancer clusters...

[lpangelrob]

Perhaps this will turn out to be a partial explanation for the "cancer clusters" you read about every now and then.

If, and only if, the occupants of these clusters turn out to be vampires.

It's not even really LIKE a normal cancer...

[ScentCone]

... in the sense that these are not the dogs' own cells. This is much more like the dog being a petri dish for a parasitic cell that's being physically passed along, almost like bacteria. The cells just set up shop in the new dog's tissues.

Slightly annoying, in TFA, is the notion that "DNA will try anything to reproduce itself." That might want to read more like "just about everything happens to DNA as it's cloned, and sometimes the mutations work better, and sometimes they fail." There's nothing worse than anthropomorphizing your description of cellular mechanics.

Re:It's not even really LIKE a normal cancer...

[axolotl_farmer]

The cancer cells are mutated dog cells, only that they originated in another dog maybe 1000 years ago. The new discovery is that the cancer cells can infect other dogs. Usually, cells from another individual (even cancerous cells), are recognized as foreign and destroyed by the immune system.

Re:It's not even really LIKE a normal cancer...

[Gospodin]

There's nothing worse than anthropomorphizing your description of cellular mechanics.

I'll take hyperbole for $1,000, Alex.

Re:It's not even really LIKE a normal cancer...

[aeve]

I liked that line in the article--it shows the writer is familiar with Richard Dawkins' "The Selfish Gene" (http://en.wikipedia.org/wiki/The_Selfish_Gene). The only "human" emotion the statement gives to DNA is the "will to reproduce" and while the DNA isn't consciously trying different strategies, the mechanisms that introduce the mutations are built from the DNA's template. In Dawkins view, us humans (and dogs, and transmissible doggy sarcoma) are just the bags of machinery that the genes build to help them replicate themselves.

So maybe assigning the "will to reproduce" to humans is DNA-morphizing anthropos.

Re:It's not even really LIKE a normal cancer...

[digitalhermit]

There's nothing worse than anthropomorphizing your description of cellular mechanics.

Interesting sentiment... Funny how we can talk of "mind" as opposed to "brain" and nobody raises an eyebrow. The idea of consciousness is not that far removed from the idea that DNA is selecting host animals. After all, what is consciousness but the expression of chemical and electrical processes in the brain, similar to the chemical and electrical processes in DNA replication.

Re:It's not even really LIKE a normal cancer...

[trongey]

...There's nothing worse than anthropomorphizing your description of cellular mechanics.

Well, maybe cancer. Infectious cancer might also be worse.
Or having your leg chewed off by a wolverine.
Oh, oh, kidney stones, I hear they're a lot worse than anthropomorphizing your description of cellular mechanics.
And don't forget about ...

Re:It's not even really LIKE a normal cancer...

[ScentCone]

Or having your leg chewed off by a wolverine.

I've had all four of my legs chewed off by wolverines, you insensitive clod!

OK, so maybe a few things are worse than assigning a personality to a strand of DNA. I'll buy that.

Re:It's not even really LIKE a normal cancer...

[Kelson]

There's nothing worse than anthropomorphizing your description of cellular mechanics.

So true. DNA hates it when you do that.

Re:It's not even really LIKE a normal cancer...

[ajs]

Yes and no. I think the more interesting discovery is that there's a species of creature who's anscestry includes a highly evolved creature (dog) and yet is on-par in terms of lifecycle with some of the least complex (colonial microbes). This might cause us to re-think much of what we believe to be true about the evolution of simple species, which might well have gone through this reversion to single-cellular life form multiple times.

Then again, this might be rare enough that it has had little impact on the process. Hard to tell.

Re:It's not even really LIKE a normal cancer...

[mcmonkey]

There's nothing worse than anthropomorphizing your description of cellular mechanics.

So true. DNA hates it when you do that.

My DNA and I had a good laugh at that one.

Re:It's not even really LIKE a normal cancer...

[ScentCone]

So not true. DNA likes it when you do that.

Huh. I just tried to reproduce your DNA joke, but it mutated.

Re:It's not even really LIKE a normal cancer...

[plunge]

Well, things like this are basically just a reminder that mutlicellular creatures are just that: a very peculiar case of cells acting in concert, unlike most cells. In the end, it's not surprising that cells who are in some ways messed up could revert back to the more standard behavior of not working with the group.

Simple multicellular life is often pretty interesting in this way. Sponges, for instance, can be separated up into individual cells, and those cells will then later reassemble into a sponge again when given a chance (they even have four distinct cell types that all seem to vaguely be able to reassemble in the right way to work in concert).

How does it evade the immune system?

[neatfoote]

My understanding was that normal cancers survive in the body because they're part of its own tissue, and are recognized by the immune system as normal body cells. If, as the article says, this sarcoma really is transmitted via the cancer cells themselves (as opposed to an infectious cancer-causing agent like a virus), then shouldn't the infected dog's immune system recognize the cells as coming from another dog and attack them?

Re:How does it evade the immune system?

[Anonymous Coward]

Nice comment. You hit the nail of why this has made immunologists (and the general medical research community) very excited. It's a naturally occuring neoplastic growth that is 'non-self' but not recognised as such by the host immune system. Thus it either is able to mimic the host tissue and/or completely evade the immune system. Study of this and the tassie devil tumours may provide novel insights into ways to enable transplanted organs or cells to evade the host immune system. From diabetes to heart transplants it's another string to the bow of medical science.

Re:How does it evade the immune system?

[Lazarian]

If this is something unique among cancers, then maybe it's possible to find the mechanism that these foriegn cells are able to integrate themselves in another genetically different organism. Once that could be discovered, maybe this would lead to other approaches in combatting more typical forms of the disease. (I'm not in any medical field, but I've never heard of cancer cells acting like a parasite like these seem to do.)

After just recently losing someone close to cancer, it'd be nice to see some earth-shattering breakthroughs in the field.

Re:How does it evade the immune system?

[lockefire]

From the original article in Cell:

A recent study (Hsiao et al., 2004) shows that, during progressive growth, secretion of TGF-b1 by CTVT acts as a potent local inhibitor of host immune responses, as does the downmodulation of DLA class I and II expression observed by us and others (Cohen et al., 1984).

DLA is basically the dog immune system method of identifying 'self'. These tumor cells are hiding the fact that they are not-'self' well enough that they easily overwhelm any immune response.

Tasmanian Devils have it worse...

[aapold]

Tasmanian Devils are being wiped out by a transmissable cancer called Devil Facial Tumor Disease, its a pretty hideous disease that eventually causes the animals to starve to death as they are unable to eat. It is transmitted when Tasmanian Devils fight each other. It is estimated 100% fatal within 12-18 months, it is estimated that over half of all remaining Tasmanian Devils in the wild have it, and it has decimated their population.

Re:Tasmanian Devils have it worse...

[slyborg]

Looks like evolution in action. The least aggressive TDs will survive.

Re:Tasmanian Devils have it worse...

[stonecypher]

Yes, it says that right in the slashdot story. By the way, Decimate means to destroy one tenth of.

Re:Tasmanian Devils have it worse...

[mlyle]

By the way, Decimate means to destroy one tenth of.

Nice try, but since approximately when the word began being used in English it was also used rhetorically or loosely for destroying a large fraction of something.

For example, from the OED:

1663 The...Lord...sometimes decimates a multitude of offenders, and discovers in the personal sufferings of a few what all deserve.
1812 An expurgatory index, pointing out the papers which it would be fatiguing to peruse, and thus decimating the contents into legibility.
1848 Typhoid fever decimated the school periodically.

I know you like to rely excessively on etymology, but come on-- the word only entered usage in English in the 16th century and was used in this loose sense in some of the earliest recorded uses. The fact it came from decimare is immaterial. I suggest you cut the pedantic etymology posts until you're better educated. I've added you to my foes list as this is the third post of yours I've seen with this tripe.

For that matter...

[brunes69]

For that matter, how the hell are these foreign cells growing **whole tumours** in the host without the host's immune system going into complete overdrive?

I mean, it's hard to even transplant a finger in a human without using huge amounts of anti-rejection drugs. How is there a tumor growing inside the dog, with cells that must have a totally different DNA and chromosone pattern? Why is the dog's host system not attacking it?

I mean, part of the whole problem with cancer is that the cells are in fact your own cells, so your body never attacks the infection. But if the cancer is directly contagious than this is not the case at all.

Re:For that matter...

[CastrTroy]

I think it has something to do with how close the cells are to the cells of the host. In the case of cancer cells, they contained somewhat damaged DNA, which is the cause of the tumour, yet your body still doesn't attack it, because for some reason or another it doesn't see it as a threat. I think the same thing would apply here. Remember that all breeds of dogs are the same species, even though there's a wide variation of DNA out there to account for all the different breeds. Perhaps dogs have a much larger margin which their body considers safe for presence in their own body due to such a large variation in the genes present in the species.

Re:For that matter...

[Ford Prefect]

From the article linked from elsewhere in the comments:

The scientists found that the Sticker sarcoma cells make very few of the surface proteins that vertebrates use to distinguish self from non-self. It appears that the tumor cells can avoid an all-out attack from the immune system. Instead, the immune system reins in the cancer cells, which can survive in the dogs even after their tumor disappears.

It's ... evolved.

Re:For that matter...

[plague3106]

Do you think that blood cells from a black person attack blood cells from an asian person?

Re:For that matter...

[crabpeople]

RTFbA

The team further found evidence that CTVT has adapted to evade dogs' immune responses. Otherwise, the unrelated tumor tissue "ought to be rejected," Murgia said.

Interestingly, he added, most dogs infected with CTVT develop a tumor that then regresses several months later and disappears.

"It looks like there is an aggressive phase of growth as the foreign tumor initially isn't recognized by the immune system," Murgia said. "In the long run, the immune system gets the better of it."

http://www.whatsnextnetwork.com/health/index.php/a /2006/08/10/contagious_cancer_in_dogs_confirmed_br oa

Re:For that matter...

[stonecypher]

I mean, part of the whole problem with cancer is that the cells are in fact your own cells, so your body never attacks the infection.

Actually, the human body attacks cancers with an amazing speed and dedication. That's why when you get an immune suppressive disease like HIV, GRID or Hep C, you start getting all these weird cancers that nobody ever gets. The most common in the case of AIDS patients is Kaposi's Sarcoma, which is caused by a strain of herpes that we all have (HHV-8,) because once our natural resistance to KS is gone, it spreads like wildfire. Doctors suggest that we each actually get two cases of KS every week, and that we just give the cancers the beat-down.

Similarly, there are many cases in which the body attacks its own cells - sometimes by design, such as immune response to a cut, where the white cells kill themselves to provide the mass for a seal (pus and yellow scabs,) in tumor and growth suppression, to prevent bone spurs, etc; sometimes by disease, such as with lupus, perineoplastic syndrome and so on.

I mean, it's hard to even transplant a finger in a human without using huge amounts of anti-rejection drugs.

That's because legitimate tissue is covered in markers, so that they're easy to tell apart. These cells, like parasites, simply don't express almost any such markers. It turns out that our immune system ignores what it can't identify, and in this specific case, these tumor cells have become remarkably adept at hiding their identity. They're like Russian spies: they just blend in really well, and so nobody singles them out.

How is there a tumor growing inside the dog, with cells that must have a totally different DNA and chromosone pattern?

The immune system can't check DNA.

Why is the dog's host system not attacking it?

Because it doesn't know they're foreign. Parasites do this all the time; the human immune system manages to miss several dozen bloodworms (tape worms but in your veins, and six meters long) in the average equatorial African. The immune system doesn't get patched every friday, like your virus checker does; the only way to get something into it is if it makes a big enough difference for the change to provide an evolutionary advantage. Very few parasites are noticed by the immune system; the ones that are are the ones that are either there briefly, presumably to eat, or the ones which are strong enough to fight off the host's immune system, which is rare.

By the by, that's why sickle cell anemia isn't actually a disease. It's a partially complete adaptation: malaria can't kill someone with sickle cell, because it can't burst the oddly shaped cells. That two or three times in one's lifetime it might cause near-fatal crisis, because the sickle cells get stuck, is significantly less dangerous than being susceptible to malaria; indeed, that we're stepping in with medicine right now is unfortunate, because another two thousand years or so, and we'd be immune.

Re:For that matter...

[MichaelSmith]

Could a similar mechanism transfer genetic material between human hosts? And could this be one way for those humans to evolve, or at least change?

Re:For that matter...

[mpe]

Very few parasites are noticed by the immune system; the ones that are are the ones that are either there briefly, presumably to eat, or the ones which are strong enough to fight off the host's immune system, which is rare.

Potential parasites which do get noticed are unlikely to be sucessful in the first place.

Re:For that matter...

[plunge]

Actually, this is incomplete. The advnatage of sickle cell isn't JUST the fully expressed form. Some immunity also exists in people who have only one copy of the gene, and without anywhere near the same sorts of horrible side-effects. So the tradeoff may not be "full blown sickle cell helps prevent malaria" but "the price for many many people having an immunity to malaria is that a smaller subset of people will get both copies of the immunity and hence experience terrible side-effects."

In case you needed another reason...

[toxcspdrmn]

...not to lick your dog's backside.

Re:In case you needed another reason...

[Randolpho]

In case you needed another reason...

...not to lick your dog's backside.

But....... yum!!!!!

Re:In case you needed another reason...

[Alsee]

The article says it's also sexually transmittable...

-

Cancer..... sounds more like a new life form

[jjh37997]

Weird..... these cancer cells have evolved an ability not only to metastasized to different parts of a dog's body but to other dogs too. At this point I really don't think we should call them cancer cells anymore..... they are a new type of free living organism.... like a parasite. I wonder why they are restricted to only infecting other dogs? Does interspecies transmission produce too much of an immune response in a different host?

confusing

[i_should_be_working]

FTA:
A cancer cell is usually an animal's or person's own cell..

..the cells are not genetically related to the dogs they are in -- proof that they did not arise from the dogs' own cells.

..all the tumor cells, no matter where they were collected, are clones of each other.

If every cell of this cancer is a clone, and not the dog's own cells screwing up, then I'd say this is more like an infection. An alien organism has invaded the dog's body and then replicates. What's the difference (in terms of the vector) between this and a bacterial infection (also single-celled)?

Re:confusing

[stevesliva]

An alien organism has invaded the dog's body and then replicates. What's the difference (in terms of the vector) between this and a bacterial infection (also single-celled)?

The alien thing is a dog cell, not a bacterium or a virus or a protozoan or a prion or a parasite. It is an infectious disease, yes, but a different variety. If a doctor exclaims, eureka, malaria is caused by a protozoan and not bacterium, and you respond, "well, same difference," then you should stop reading general interest health science articles.

Re:confusing

[annakin]

The OP was right. It all looks the same to the immune system. By way of example, someone asked if there were any varieties of dog that had an immunity to this cancer, and I was tempted to reply, "Yes, all of them."

The OP didn't say it was a protozoan, he said it was an infection, and on that point, he is correct.

Re:confusing

[ajs]

The OP was right. It all looks the same to the immune system.

Good gods no! To the immune system, this would look very different from an infection. For starters, it's going to appear to be "mostly dog", that is, many of the markers that prevent the immue system from attacking will be expressed. Bacteria don't do that, at least not on this scale (though they might mimic the host's markers enough to bypass some of the more common defenses).

No, this is going to look more like a parasite or perhaps some sort of contamination (e.g. blood or other fluids that were exchanged during sex/combat/etc.) from another dog.

The curious part is how this cell defends itself against the immune system. That's a pretty impressive trick, and one that humans haven't been able to match.

Re:confusing

[stonecypher]

If every cell of this cancer is a clone, and not the dog's own cells screwing up, then I'd say this is more like an infection. An alien organism has invaded the dog's body and then replicates. What's the difference (in terms of the vector) between this and a bacterial infection (also single-celled)?

Not much. That's why it's called a contagion. The nature of the contagion is still that of a highly specialized dog cancer. Similarly, nano-robots breeding on the iron in your liver would be a contagion; that wouldn't make them any less robots.

Sorry, I'm watching Star Trek.

Re:confusing

[annakin]

I think, based on my personal, and arm-chair experience with the immune system (and my personal experience is rather extensive at this point), that the immune system is far more capable of battling cancers than bacteria. Cancer is expected in the lifecycle of any organism, so over thousands of years of evolution, the immune system is quite effective at shutting it down. Cancer's danger is in malignancy, or its ability to outpace the immune system with sheer growth, and nestle itself in obscure corners of the body where the immune system has trouble reaching.

On the other hand, there is evidence that the body is naturally filled with many types of bacteria, and that internal bacteria may represent a stable ecosystem. The success of antibiotics seems to support this, as antibiotics seem to do a job that the immune system cannot do. Of course, with facial acne it's clear that the immune system can fight bacteria, it just doesn't seem to be one of its strengths.

I wonder where all of this fits into standard immune theory. I opened up a book called "Intro to Immunology" over the weekend and it was all math.

spread the word

[Mantooth]

teach your kids the dangers of red rocket

Re:spread the word

[smenor]

... but spare them the horrible burden of knowing about the bulbus glandis.

If this spreads to cats...

[Iphtashu Fitz]

...then I'm leaving the planet. This was all predicted in the original Planet of the Apes movies...

Re:If this spreads to cats...

[Dorceon]

You know if you leave the planet, you'll just crash here again in the distant future. (After those bastards blow it all up, of course.)

Re:If this spreads to cats...

[Iphtashu Fitz]

Yeah, well somebody will have to make sure the Ape Army finds the hidden world of the Omega bomb worshipers and detonates the bomb. If humans can't control the planet then damned dirty apes sure can't be allowed to.

Sad

[Damastus the WizLiz]

Part of me feels very sorry for all these poor animals. Another Part of me is really itching to make witty comments about Nature's population controls and how humans will be next.

Original peer-reviewed Cell link

[mapkinase]

In this table of contents go to "Clonal Origin and Evolution of a Transmissible Cancer". Summary:

The transmissible agent causing canine transmissible venereal tumor (CTVT) is thought to be the tumor cell itself. To test this hypothesis, we analyzed genetic markers including major histocompatibility (MHC) genes, microsatellites, and mitochondrial DNA (mtDNA) in naturally occurring tumors and matched blood samples. In each case, the tumor is genetically distinct from its host. Moreover, tumors collected from 40 dogs in 5 continents are derived from a single neoplastic clone that has diverged into two subclades. Phylogenetic analyses indicate that CTVT most likely originated from a wolf or an East Asian breed of dog between 200 and 2500 years ago. Although CTVT is highly aneuploid, it has a remarkably stable genotype. During progressive growth, CTVT downmodulates MHC antigen expression. Our findings have implications for understanding genome instability in cancer, natural transplantation of allografts, and the capacity of a somatic cell to evolve into a transmissible parasite.

This is just great. This is worse that prions.

Re:Original peer-reviewed Cell link

[stevesliva]

This is worse than prions.

I don't think so. You can quarantine this, and stay away. With prions, you never see them coming. And then your brain melts.

Re:Original peer-reviewed Cell link

[imsabbel]

Its not.
Its not even deadly, as most dogs immune system will be able to supress the infection in a matter of months.
Those "external tumor infections" have all the weaknesses of living cells without the protection a normal cancer cell has by being hard to distinguish from "good" cells. (while prions are just a pain in the ass to kill)

Re:Original peer-reviewed Cell link

[Hal_Porter]

Still it might be kind of useful that these are universal dog cells - they can grow in any dog without triggering an immune response. I guess that's what 'downmodulates MHC antigen expression' means. Imagine if you had universal stem cells that could be used to 'repair' anyone.

Admittedly injecting people with things like this seems to have a high cancer risk, but maybe you could make a sort of anti-cancer with a much reduced hayflick limit rather than a much increased one. You could build in a safety measure too, like a sensitivity to a drug which is harmless to most cells. Maybe more than one drug actually, since they may develop drug resistance.

Re:Original peer-reviewed Cell link

[stonecypher]

Actually, you're host to tens of millions of prions right now. Very, very few of them are damaging.

rebuild the original dog

[2008]

Well, if you repaired whatever damage occurred to turn the cells cancerous you could recover the original dog!

Try doing that with bacteria.

(I Am Not A Biologist, so this is quite likely a stupid idea)

How about other forms of cancer?

[Unequivocal]

Makes me wonder if other forms of cancer might turn out to transmissible? Yikes.

Wouldn't it be ironic if some of the tendency of families to be more susceptible to the same form of cancer turns out to be related to the fact that family members often live together or go and visit when a relative has a serious cancer? Eweesh.

If you think AIDS has stigma - wait until some researcher finds a hint that some forms of human cancer may be transmissible through contact or otherwise.

Re:How about other forms of cancer?

[jbeaupre]

On the one hand, I think that scenario is going to be extremely rare. On the other, cancer due to viral infection (often spread in a family) is turning out to be more common than thought with the same devistating effect.

Re:How about other forms of cancer?

[annakin]

>If you think AIDS has stigma

Congratulations, you win an award for bringing up the non-transmissible non-example.

Read Duesberg, Virusmyth, or watch The Other Side of AIDS.

Re:How about other forms of cancer?

[stonecypher]

Wouldn't it be ironic

Nope. Bargain basement word-bins like Merriam Webster aside, irony is a form of word play.

Re:How about other forms of cancer?

[annakin]

Great, so you know what I'm talking about.

"I know the truth about AIDS but I would rather troll." Oh boy.

Re:Kill all the dogs!

[k3vlar]

I see that you have never owned a cat or dog. It can be a very rewarding experience, caring for something like that.

Having said that, I agree with your views about how some people seem to value the lives of animals over other human beings.
I saw a commercial once that truly sickened me. They were asking for donations to help save captive bears in an empoverished third world country! I couldn't believe that someone could ask for money to save bears, instead of helping the PEOPLE that couldn't afford enough food. The bears were being held captive to be put on display to earn donations from passers-by, and I thought, "How stupid can this donation organization be! Solve the people problem, and you also solve the bear problem!"

Animal rights groups sicken me sometimes.

Re:now..

[ooMissioNoo]

oops... i thought it sayd university of michigan

We did a survey

[Rik Sweeney]

The dogs said that it was a "Ruff" deal...

The Tasmanian Devils just spun around quickly, said something completely incomprehensible and blew a rasberry...

simple

[r00t]

It's a dog infection. Dogs can get infected by dogs.

If you prefer to be less specific, it's an animal infection. The dogs get infected by animal cells.

Re:yay, bird flu mkII :(

[StarfishOne]

Attack of the Clones =/

test of species differentiation?

[stites]

These tumor cells will grow in any dog. It would be interesting to see if they will infect closely related species. Will they grow in wolves, coyotes, jackals, etc.? Are there any breeds of dogs which are immune to these tumor cells? Will they grow in prey bitten by a dog, such as rabbits? One possible use for these tumor cells could be to determine how closely other species are related to dogs.

----------------
Steve Stites

Re:test of species differentiation?

[lexarius]

It would be interesting if this was a skin cancer which produced hair follicles. Imagine getting bitten by your dog and, as the tumor progresses, find yourself sprouting wolf fur. Lycanthropy anyone?

Re:test of species differentiation?

[stonecypher]

These tumor cells will grow in any dog. It would be interesting to see if they will infect closely related species. Will they grow in wolves, coyotes, jackals, etc.? Are there any breeds of dogs which are immune to these tumor cells?

Agreed, that's a very interesting question, though it'd be difficult to test ethically, and given that we don't know the transmission rate, it might take a tremendous number of animals, which is costly and time consuming. Mind you, I think it'd be worth it, but it leaves a university open to fire from animal rights groups, so it's definately a very difficult topic to approach.

Will they grow in prey bitten by a dog, such as rabbits?

Of course I don't know for certain, but I can make an educated guess. In most cases, cells from animal one can't live in animal two before you even consider the immune system. The chemistries are different: more sugar, less salt, different kinds of ion channels. The neighboring cells are the wrong size and shape; imagine trying to build 7x7 lego blocks into a design made out of 5x13s. Cells require significant communication support, to control various processes; the communications markers are different. Senescence is suppressed in cancer cells, true, but there are other support processes going on. Moving a salt lake fish to the ocean will kill it based on salt content alone; either in a freshwater lake similarly. This is a lot more than just salt content, and it's got a much less complex and capable organism making the transition.

That said, there are odd cases. The environmental needs of several bacteria have led to their being hosted in our gastrointestinal tracts. It's as much an issue of coincidence as anything: they were close enough to eke out a living, and they did something useful, so we adjusted to let them, and consequently us, flourish. The common example is (IIRC) e. cola performing the valene->isovalene transition: it eats half and converts the other half. That's useful because isovalene is an important amino acid, and we're not able to make it on our own.

Now, in the case of cancer, right now it's not really doing anything bad. At least, not on cancer scale: it's uncomfortable, and that's about it. Not much for cancer. But, here's an odd thought: what if this cancer began to help the host, in the way that e. coli does for us? One possibility is that a branch of this cancer becomes chitinous, which would lead to a thicker and tougher skin. This could make the dog much hardier in combat without changing its fundamental developmental makeup. Dogs which adapted to be available to the transmissable cancer would thus become more apt to survive combat. Indeed, the genetic exchange that would happen between the transmitted cells and the host dog would lead to a higher rate of odd cancers in the host dogs which were relatively weak, since they were on differing cells whose genomes were already only somewhat stable, and as a result, dogs would have a gentle pressure towards a stunningly broad range of cancers. If dogs came to select for this cancer, it could make them largely immune to many others.

This in fact could be a very highly versatile source of genetic material in the long run.

Will they host in rabbits? Probably not. Will they host in some prey, somewhere? The chances are low, but not zero. Consider also that prey are smaller, which means cancers hit them harder, and if prey got bitten by a dog, cancer is the least of its problems; chances are good that if a rabbit was bitten by a dog, even if it got away, it's not lasting the night. The circumstances to infect a host and have it survive, let alone a broad enough range to find a suitable host, are very low.

But sure, it's possible. Monoclonal colonies get genes from invading bacteria all the time, and lots of people believe this is how hemoglobin was introduced (as a parasite - it's very, very different from the rest of the genome) into the animalian seed line.

Weirder things have happened. They're just uncommon.

Re:Good thing

[really?]

Well, most slashdotters have nothing to fear, being a geek almost never goes with being a "dog". In fact, I would say they are opposites.

Some Informative Links

[JoshDM]

A Readable Technical Discussion of Stickers Sarcoma and Canine TVT - 2004 to Congress.

Excerpt on Geographical Distribution from the latter: TVT is seldom or no more detected in North and Central Europe and in North America, mainly due to the population control of stray animals, the preventive pre-breeding examination and the effective treatment of clinical cases. With a few exceptions, TVT remains endemic in the rest of the world, obviously because of the uncontrolled population of stray dogs and the inadequacies of exerting effective treatments.

I wouldn't be too sure about that...

[amemily]

My neighbor's neutered dog was going at it with my siberian the other day.

Re:Kill all the dogs!

[Anonymous Coward]

Your post would make sense if people donating money to relieve poverty was mutually exclusive for people donating money for animals. Which it isn't. Don't let logic get in the way of your prejudice though.

p.s. Most bears have their gall-bladders milked and sold for quack medicines. They're far more valuable that way.

This is a new species of dog...

[Andrew00]

which is single-celled, asexual and an obligate parasite of dogs.

Evolutionary Logic

[alizeecat]

Organ Rejection: It's a feature not a bug

I remember a report a while ago that mothers carried some leftover fetal cells in their blood even decades after giving birth. Makes me wonder...

Re:Evolutionary Logic

[Red Flayer]

Organ Rejection: It's a feature not a bug

Except that the tumors in this case dodge the organ rejection mechanisms of the host -- antigen expression in the tumor is suppressed, so the host has no way of identifying the tumor as foreign.

So maybe it would be bettr to say:

Avoidance of histological response to a parasite: it's a feature of a bug.

Re:now..

[An anonymous Frank]

perhaps due to lack of lubricant, but still, what is the point of your reference? if you're not worried about the canine homosoexual agenda, then why post such a comment? --Or am I missing something here?

uhoh!

[mottie]

What happens when one of those weirdo ladies "accidentally falls asleep" on her couch and wakes up to her [infected] dog licking her? Is it contained to dogs, or do we have the next human version of cancer on our hands?

Nice try

[Bozdune]

Far more likely that one of our fellow idiots will figure out some way to use this new discovery to kill us all.

Lots of causes of cancer; don't avoid the park!

[StefanJ]

I'm sorry to hear about your dog, but don't beat yourself up about it, or let this deter you from taking future dogs to the park to socialize.

The transmissible cancer described in the article sounds like a very specific, sexually transmitted illness.

Anyway, dog parks aren't doggy sexual playgrounds. Most specifically ban she doggies in heat, and I don't think play-humping would do the trick.

Careful!

[ScentCone]

Funny how we can talk of "mind" as opposed to "brain" and nobody raises an eyebrow. The idea of consciousness is not that far removed from the idea that DNA is selecting host animals.

It's a question of degree of complexity. There simply isn't enough processing horsepower in a single cell to provide the framework for what we comfortably refer to as a mind. So, I would actually would "raise an eyebrow" is someone attributed cognition and volition to a strand of DNA, but have no trouble assigning "mind" capabilities to very complex brains. DNA doesn't select host animals, it either succeeds or doesn't in the host into which it's placed. That's a world of difference.

Re:Careful!

[digitalhermit]

Then you quickly run into the homunculus argument and that's slippery. At what point does complexity give rise to "mind"?

Re:Careful!

[ScentCone]

Then you quickly run into the homunculus argument and that's slippery. At what point does complexity give rise to "mind"?

See, the beauty of my armchair bio-sophistry, here, is that I don't have to be able to point at a particular degree of complexity or set of environmental/developmental circumstances and say, "Riiiiight... THERE! That's where/when mind happens." All I have to do is say that a single strand of DNA cannot handle it, as it sits. Which was my point, really. Just because complexity IS required (obviously), doesn't mean I have to nail down the particulars for my sentiment to be essentially correct. Of course, it's Friday afternoon, and my DNA's expression of alcohol-ready metabolism may be playing a role, here.

Great, another reason not to leave my house...

[wwiiol_toofless]

Contagious cancer? As if I didn't have a million reasons to stay a pasty, game-addicted, furtive and nervous agoraphobe. If it can happen to our canine brothers, it can happen to us.

Re:Great, another reason not to leave my house...

[rapidweather]

I have a cat.
His name is BeBe, because he has a BB in his b-hind.

Cats are just as loyal as dogs, mine wants to hang around me all the time. If I wash the car, he wants to sit out there and take in the car-washing scenery, and does not mind getting wet.

When it is time to go to sleep, he always follows me, and gets in the chair beside the bed and goes to sleep.
Problem is, come 4 AM, he wants to go outside and use the kitty-toilet. He is housebroken.

Cats do want to go outside in the early evening, and survey the landscape for "ememy cats", but will come in later if you call them.

Cats need to go to the Vet just like dogs, and get shots and a yearly exam. They can get fleas, so Frontline must be applied to protect them. They have to have Heartguard, too, to protect them from heartworms, which do kill dogs regularly. Cats that can get bitten by mosquitoes can get heartworms also.

BeBe always purrs when you pick him up, he is a gentle cat and likes being around people. He will play with a toy mouse on a string all you want.
If you adopt a cat, have it checked by the Vet before becoming too attached, the animal may have feline leukemia, and would have to be put to sleep.

I adopted my cat, he was abandoned in my neighborhood, and I took him in. They say men prefer large cats, and that is what BeBe is, much larger than normal. Look at the bridge of the cat's nose. If it is broad, like a tiger or cheeta, then you have a big animal. If it is narrow, then you have a smaller cat, less likely to frighten strangers who are not used to your cat.

There is a sign in the front yard, to warn of the "attack cat" there. He does look the part, and I love that.

Most importantly, you won't have to worry about your cat as much as a dog. Cats can take care of themselves, and will stay in their territory if they have a home there, with an owner, food, water, and a place to hide when there is thunder and lightning.

Cats will bring you dead rats, birds, etc. to show that they are a good cat.

Who said, "It does not matter if a cat is black or white. If it kills mice, it is a good cat."

I have seen this quotation attributed to Deng Xiaoping, but I think it was Mao Tesung, probably in Mao's Little Red Book of quotations.

--Rapidweather

In humans

[future assassin]

If this did happend in humans, wouldnt the body react to a foregin cell and attack it before it had a chance to spread?

If the body didnt detect these cell then it could also be possible to use these kinds of cells to grow new body parts that wouldnt be rejected by the patients body.

Re:In humans

[whitehatlurker]

I'm not certain what is the "this" you refer to ... I'll assume you mean invasion of a human host by the canine tumor cells. The immune system should recognise these as "non-self" and destroy the cells. If you meant that if a human tumor cell developed under these conditions, what would happen, it is likely that it would follow a similar process to the canine one.

The tumor cells are differentiated, not "stem" cells. You can't use them to grow other types of cells. No new body parts for you ...

Rejection

[wordsofwisedumb]

Could this be used as a method for keeping people from rejecting transplants? The cancer is different genetic material from the host dog, it probably also used different blood type in its previous host, but it seems that the dogs bodies don't reject it. I don't know anything about cell rejection so I could be completely wrong. Are there any doctors that could explain it?

Re:Rejection

[plague3106]

I don't think so; cancer, by definition, is uncontrolled cell division. So it could regrow the hand, but it wouldn't stop.. (assuming you could get it to be hand cells).

Re:Rejection

[stonecypher]

Could this be used as a method for keeping people from rejecting transplants?

Unfortunately, no. The issue here is that this tumor line has learned to never grow its chemical markers in the first place. You can't just knock those markers off of the surface; they're there for reasons other than identification. It's a bit like looking at the back of a computer. You can tell if it's the same kind as your computer at home, because the power cord's over here, and the switch is there, and the monitor plug is here, but the keyboard and mouse plug are over here, and they're colored and yours aren't. You can't just remove all those from a transplant; they're needed.

This tumor is more like a network slab. It has a power line and a network card, and everything else is just gone. It doesn't need a monitor plug because it doesn't care if anything can see what it's thinking. It's not a computer, it's a cluster parasite. The thing is, the way the immune system works is to say "that shouldn't be there," or "that shouldn't look like that." It's too dumb to say "omg where is this, it's not there at all." Because the slab is just missing essentially all its surface, it's completely faceless to the immune system, and so the immune system basically treats it like dust. It clusters it into one spot and tries to secrete it. In the case of actual dead material, that comes out in exfoliation. But, since these are cells, they attach just like any other cells, and end up sticking around.

The cancer is different genetic material from the host dog, it probably also used different blood type in its previous host

The immune system would have to tear a cell in half to see its genetic material. Therefore, the immune system can't see its genetic material. Similarly, since these are individual invading skin cells, they're not making blood, so the host dog has no idea what blood type their genome suggests.

but it seems that the dogs bodies don't reject it.

Think of them as Russian spies in a cold war movie. Why aren't the police putting them in jail? Because the police have no idea they don't belong. Much like movie spies, these cells look like the locals, act like the locals, talk like the locals, and are essentially just too featureless to pay attention to. I bet this cancer drives a Chevy and goes to PTA meetings.

To be clear, the reason this cancer is succeeding is that it has adapted to stealth.

I don't know anything about cell rejection so I could be completely wrong. Are there any doctors that could explain it?

You're in the right neighborhood; normally you'd be correct. You just didn't realize what this tumor is doing differently. It's sly; stealthy. I have made a diagram to assist in your understanding of why the immune system cannot flush this cancer.

Re:Rejection

[wordsofwisedumb]

Thanks!

Great diagram too!

Which is why...

[jd]

...the cancer cells are identical. Not merely "similar", in that they're cells of cancer type X, but a direct copy of the original cancer. (The genes that are present are from a husky, if I understand the story correctly, and the markers are clear enough to be able to estimate a timeframe. This is how they know the origin, as opposed to finding said husky in a glacier somewhere.)

This story has a lot of implications that aren't necessarily obvious. First, if both dogs and marsupials can have a contageous, directly-transmissable cancer, then so can any species, through ANY mechanism that involves a transfer of cells. I wonder if blood banks are being screened for such cancers. Given the total lack of speed they showed over AIDS or vCJD, I seriously doubt they've got any serious monitoring in place for such pathogens. (Sure, it's a theoretical, but it would seem better to KEEP it a theoretical, rather than wait until it's a major problem.)

Since this was presumably two different spontaneous mutations, transmissable cancer must be capable of arising in almost any organism at almost any time. I doubt there would be many carcinogens in common between Alaska and Australia, despite them having the same first and last letters. Understanding that mechanism would seem very important, as it would seem reasonable to assume that anything that easy to start would be equally easy to stop.

Finally, for the cancer to spread in the way described, we must be talking about cells with a high degree of mobility. This can't be something attached to something, like a tumour, or it couldn't spread identically from organism to organism. It must also be fragile enough that an airborne version has not yet evolved. However, that may be merely a matter of time. I think medical labs should be putting the effort into understanding the mechanisms and the limitations of transmissable cancers, as we really don't want to be in the usual mess of playing catch-up afterwards, but don't need to do more than necessary if research shows that the limitations are barrier enough.

Re:Which is why...

[RDW]

"First, if both dogs and marsupials can have a contageous, directly-transmissable cancer, then so can any species, through ANY mechanism that involves a transfer of cells."

If you want a really scary Michael Crichton scenario, the authors reference work done in the 60s (this isn't a new idea) on another possible contagious tumour that "can even be transmitted via mosquitoes". Luckily that one was in hamsters.

Re:Which is why...

[RsG]

Finally, for the cancer to spread in the way described, we must be talking about cells with a high degree of mobility. This can't be something attached to something, like a tumour, or it couldn't spread identically from organism to organism.

I could be way out of line here, but I'm pretty sure that metasticized cancer cells have a high degree of mobility in normal, non-contagious cancers. The ability to jump from one organ to another via bodily fluids doesn't seem that far removed from the ability to jump from one organism to another via those same fluids. So I don't think the distinction here is mobility.

Part of what's unusual about this strain of cancer is mentioned in TFA:

Studies suggest that, unlike most tumor cells, which contribute to their own demise by becoming increasingly genetically fragile, Sticker's tumor cells are remarkably genetically stable, perhaps explaining in part their evolutionary success.

So the cells are unusual, at least when compared to other forms of cancer.

Another thing I find odd is that the dog's immune system doesn't recognize these cells as foreign and attack them; one of the reasons that your own immune system has trouble attacking your own cancer cells is because they're identical to the host's. OTOH, they say the cancer isn't fatal in dogs, so it's quite possible that the immune system does limit it's development.

Re:Which is why...

[Reziac]

[Hat: I am a professional dog trainer and breeder with 37 years experience.]

I first noticed an apparently-contagious tumour in dogs about 15 years ago. Transmission seems to require direct contact (not necessarily venereal), and the growth is always located in or just under the skin. Superficially, it resembles an ordinary fatty tumour. Under the microscope it looks like it's not exactly benign, but not like a "hot" cancer either. I've never seen one develop into anything serious.

Re:Which is why...

[feepness]

I wonder if blood banks are being screened for such cancers.

I am a cancer survivor and can tell you at least that the blood banks are explicitly not interested in me donating.

Whether they actually can/do screen I don't know.

Re:Which is why...

[WilliamSChips]

I can confirm this because my mother, who has survived lymphoma(I think that's how it's spelled), can no longer donate blood.

Re:Which is why...

[HaveNoMouth]

Another thing I find odd is that the dog's immune system doesn't recognize these cells as foreign and attack them; one of the reasons that your own immune system has trouble attacking your own cancer cells is because they're identical to the host's. OTOH, they say the cancer isn't fatal in dogs, so it's quite possible that the immune system does limit it's development.

The link (above) on Tasmanian Devil cancer says that in the case of that species, the lack of genetic diversity caused by inbreeding in the wild has made the cancer unrecognizable as "foreign" to the animals' immune systems. I suspect this would rule out a similar mechanism for cancer transmission in humans, except perhaps in Alabama.

Re:Which is why...

[plunge]

Are you sure this is because of the cancer, or the treatment? I may be 100% wrong, but I think this is in part because of the lasting effects of things like chemo on the blood, not just the cancer.

Doggie Cancer Kills

[blooba]

I borrowed my nickname "blooba" from my late dog. I lost him to cancer last year. I spent $10,000 trying to treat his mast cell tumors, and I think I gave him a few extra months of comfortable living before the fucking cancer metastisized like a fucking wildfire. Anyway the point I'm trying to make is that it wasn't until after I put him down that his team of highly trained veterinarian oncologists at Manhattan's most prestigous Animal Cancer Treatment Center told me that canine cancer has a 100% mortality rate.

I sure wish I had known that before I shelled out $10,000. Don't get me wrong. My dog was worth every penny. But it sure would have been better to know beforehand that there was absolutely zero chance of him surviving cancer.

The main problem is the lack of animal cancer research. The good doctors who treated my dog (and he had an entire team of surgeons and specialists) tried very hard, but they just don't have enough information. Doggies don't respond to chemo like humans do, and they don't respond to radiation like we do. The doctors have to play extreme guessing games with each patient. It's all trial-and-error.

Before he passed, dear old Blooba donated a sample of his blood for research purposes. He always was a generous soul.

Re:Doggie Cancer Kills

[Rix]

You have some very strange and messed up priorities if you're seriously calling for spending research money on canine rather than human cancer research.

You probably could have saved a person with that $10k.

Re:yay, bird flu mkII :(

[Ana10g]

Don't bite your dog, or sleep with it, and you should be fine.

This just in...

[Jason9x19]

When reached for comment, one Tazmanian Devil had this to say, "Blaugaugaguagaghag *SNORT*"

Re:yay, bird flu mkII :(

[Burlap]

its the licking im worried about. How many times do you let a dog lick the back of your hand to gain it's trust? or see one licking a kids face?

Mutation

[jeebus81]

Im particularly concerned about the possible mutation of the cell to survive and thrive in human organisms...prognosis negative

Could cancer be a form of evolution?

[Anonymous Coward]

Is it possible that cancer is a form of evolution? If you think about it, a rogue clump of cells that somehow (1 chance in a gazillion) finds a purpose that extends an animals life and gets passed on as part of the genetic make up. Quite often cancer runs in families, unfortunately pretty much all of the time it is destructive and ends up killing. If one time it is useful then if might help a species survive.

Symbiotic relationships could occur in the same way. For example, Ruminants eat and rely on billions of micro-oraganisms to break the grasses down for them. Without these organisms, they would not live.
http://en.wikipedia.org/wiki/Ruminant

The transmitable cancer in dogs and marsupials could conceivably turn into a symbiotic relationship instead of a destructive one one day.

Re:Could cancer be a form of evolution?

[stonecypher]

Is it possible that cancer is a form of evolution?

Yes, but not for the reasons you mean. Natural selection (this isn't evolution, which is a far more fundamental process) is a stochaistic system. It's not directed, but rather random and selective. It is a fundamental adaptation to derive utility from chaos.

Cancer is cellular damage. That too is chaos.

It's not that cancer is a form of selection. It's that they're both just a huge rolling of dice.

Symbiotic relationships could occur in the same way. For example, Ruminants eat and rely on billions of micro-oraganisms to break the grasses down for them. Without these organisms, they would not live.

So do we, you know. For example, the e. coli valine-isovaline cycle.

Prions?

[DeadCatX2]

Can someone explain what a prion is?

I read wikipedia on it, but all I gathered is that it's a protein which causes other proteins to mutate like a chain reaction, thereby causing sickness, and that is how it becomes infectious.

Re:Prions?

[mapkinase]

Prions are proteins that for some reason have different wicked structure that allegedly causes other proteins with the same function to adopt the same wicked structure. Those twisted proteins are susceptible to aggregation called amyloids. Those macroscopic aggregations bring major damage to important cells of the brain. They grow and grow and grow...

Something like that.

Re:Prions?

[WilliamSChips]

Priors are people who have been taken to the Flames of Enlightenment(their name) at Celestis and genetically improved to be as close as possible to Ascension without actually Ascending them. They are then used like a missionary to preach Origin to other planets. They are also a necessary component in the construction of the Ori Toiletships(not their name) which are used to kill unbelievers. Oh, wait, you wanted to know about Prions? Sorry, no experience there.

Re:Prions?

[plunge]

Well, that pretty much IS the theory about what prions are and what they do. The scary thing is that they can survive in conditions that normal pathogens (agents of disease) will not. For instance, cooking meat will kill many sorts of bacteria, but unless the temperature is enough to break down proteins, it won't destroy the prions.

And the diseases that prions cause are particularly nasty. One suspected prion disease is shared by a single extended family, and as it slowly destroys their brains, they find it less and less possible to fall sleep. This leads to waking demntia and they essentially die of a horrendous waking demented insomnia.

Pleasant dreams!

This Gives....

[pedalman]

yet another reason not to let your dog hump the guests' legs at your next party.

Ah, the optimism of youth (mine, that is)

[MarkusQ]

Not even Bush is a great enough moron to attack a nuclear power. And even if he was, I doubt Dick Cheney and the cabinet and the Pentagon are all suicidal enough to let it happen.

I think of all the things I've lost over the years, I miss my faith that there was, somewhere, a limit to human stupidity the most.

--MarkusQ

Earth, unfortunately.

[MarkusQ]

On what planet is this sort of nonsense "Insightful"?

Earth, unfortunately.

--MarkusQ

That's not a dog - anymore!

[karrot]

It's the alien species from John Carpenter's The Thing! Trust no one.

Similar to human HeLa cell line?

[kbmccarty]

This article reminds me very much of the human cancer cell line HeLa. I first heard about it in a biology class in high school, years ago. It is a cancer cell derived from a single person's cervical cancer around 1950, which is sufficiently fast-growing that (according to the Wiki article) it forms a common "weed" in lab cultures. It has even controversially been named a new species. Thankfully, unlike the dog cells, the HeLa line doesn't seem to be able to infect living humans (yet...)

Taking a canine "sickie"

[drewsup]

ME: YA, (cough, cough) boss, I wont be in today, I feel really awful (sniffle, cough). Boss: Well what seems to be ailing you?? Me: I think I caught a case of that you know ,whadaatheycallit dog cancer stuff, Its killing me. Boss: Maybe you should see a vet. PRONTO! Me: YA, I'll do that, I still get the day off though,right??

Re:Quarantine NOW!

[superpulpsicle]

That's alright. We americans eat cows, and we'll get clubbed in India for it.

Ssshhhh!

[Valdrax]

2. I'd choose bark park with a 3/4 life span vs. no fun for a long time and all the other dogs I know agree.

Sshhh! Sshh! What are you doing? On the internet, no one's supposed to know that you're a dog!

This is good!

[Commradd]

Maybe this will put an end to all the "dog on girl" pr0n.

Re:Asia

[Valdrax]

Europe already spread all of its nastiest diseases during the colonial period. It's only in the past century or so that increased global trade has resulted in more exchange of diseases from Africa and Asia to the rest of the world. Also, people in Asia and Africa live closer to the wild and have more contact with wild animals that can prove to be vectors of new diseases such as SARS and AIDS.

Re:Kill all the dogs!

[mr_mischief]

...and I could have sworn that most bears live in the wild.

Oh, no... we're doomed

[osgeek]

Why did the bozo in the article have to sentence the human race to death with this statement?

Weiss called the tumor transmission trick "a curiosity of nature."

Now we're done for. That will be the one that wipes us all out.

Remember!

[Locke2005]

"When you sniff another dog's butt, you're not only sniffing that dog's but, you are also sniffing every butt that dog has ever sniffed! Always practice safe butt-sniffing!"

Ok, now how do I explain this to my Irish Setter?

Those devils are tough

[LukeWebber]

I strongly suspect the devils contracted their disease due to their habit of gang-raping rottweilers.

Decimated?

[HornWumpus]

So they drew lots and 1 out of 10 is beaten to death by the other nine?

Harsh (it was the Roman armys punishment for unit cowardice in battle).

I hate that word. It's got to be the most misused word in America.

Re:Kill all the dogs!

[Anonymous Coward]

Simple. Just feed the excess people to the bears. Both problems solved.

Live and let die: Evolution vs. Disease

[Hoch]

As for the tasmanian devils, it seems to me to be the wrong idea to attempt to eradicate the disease. The devils will most likely evolve an immune system competent enough to ward off the face disease within a few generations. If humans intervene, this will never happen. The process of evolution of the immune system would select for outliers--animals with a varied or unique immune system--which would leave the devils in a better place when the next disease comes around. For any immune system to work well, it must be different from a significant portion of the population. Inbreeding, as in dogs, kills diversity and leaves the species vulnerable. This is somewhat acceptable in dogs, as they are cared for by people. The devils cannot have constant care while living in the wild. Nonetheless, rabid conservationists attempt to solve the problem by quarantineing devils with weaker immune systems than those that would come out of this so called crisis. This behaviour only increases the chance that the devils will have an outbreak in the future and does nothing to bolster the devil's chances for long term survival.

To recap, a disease like this thins out the middle of the population, leaving the more genetically diverse individuals with a chance to reproduce massively and fill in the void left by the wake of the disease. The result is a less genetically similar population. A second point to be considered is that the middle might be better at rapid reproduction than the outliers (because of point muations), so reinstating them could be dangerous as they will again dominate the population. If they are left on their own, quick reproduction and survival would be quickly selected for.

But alas, people love to meddle with other species especially when they are "cute and defenseless". The conservationists will manage to enstill another generation with these ethics, to the long-term detriment of many species that they wish to preserve.

I hate to break it to you...

[Rix]

But words change meaning over time. Also, English is not Latin.

Re:How about other forms of cancer? (off topic)

[Unequivocal]

Hmm. Not to split hairs with you, but maybe - maybe not. In addition to M-W, American Heritage supports my use, as does Wikipedia, though they offer some comments as to the controversy you're bringing up: Wikipedia on irony usage controversy

Moo

[Chacham]

IMHO, using a word such as that in a story lowers the standard /. has.