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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."
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
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?
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.
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.
Perhaps this will turn out to be a partial explanation for the "cancer clusters" you read about every now and then. Varka
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?
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.
"Waste not one watt!" - CZ
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?
FTA:
..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.
A cancer cell is usually an animal's or person's own cell..
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)?
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.
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Steve Stites
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.
"Some days you just can't get rid of a bomb."
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.
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.
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.
Part of what's unusual about this strain of cancer is mentioned in TFA:
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.
Erotic is when you use a feather. Exotic is when you use the whole chicken.
[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.
~REZ~ #43301. Who'd fake being me anyway?
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.
StoneCypher is Full of BS