Slashdot Mirror
Test For Prostate Cancer Gene Soon To Be Available
Tiger4 writes "CNN reports on a simple test to determine the presence of genes linked to Prostate Cancer. These five genes, if present, can increase the risk of prostate cancer up to nine times. 'More than 25,000 American men will die from prostate cancer this year. But prostate cancer can be treated successfully if the disease is caught early. A blood test that can detect whether a man is at high risk for developing prostate cancer is on the horizon. The study was published in the February 28, 2008, issue of the New England Journal of Medicine.' It turns out the company actually wants to test saliva, making the test significantly easier and more convenient. Compare this to the tests available for BRCA, the so called Breast Cancer genes. Finding you have the gene can be devastating, but knowing well in advance of developing cancer allows many more options to be considered."
Just remember that these are not genes (or, more correctly - alleles) that determine, in an absolute manner, whether you'll get the cancer or not (unlike, say in the case of the mutant gene for Cystic Fibrosis). They are variants that, when present alone or in combination increase the risk. It's a bit like with insurance - when you're a twenty-something, living in a large city, and want to insure a sports car, you'll pay a greater premium than a middle aged small-town father insuring a minivan, because the risk that you'll have an accident is several times higher. But that doesn't mean that all urban twenty-somethings in sports car will crash (in fact, most of them won't), and it doesn't mean that the minivan driving fathers never crash. It't the same with the association of genetic variants with cancer - there is no causative relationship - there is only an increase in risk. Which means that the test can be informative (to a varying degree), but is never definitive (unless it's a simple Mendelian trait, like CF, which the common cancers are not). Read this informative post on The Evolution & Medicine Review for a sobering view on genetic association in complex traits. Also, if you follow the link to the company page you'll see (in the News section) that the main paper (in NEJM) reporting the association was a study done on the Swedish population, and it's by no means certain, that it'll hold for other population backgrounds. All this doesn't mean that it's worthless, just an advice to take it with a grain of salt.
Test For Prostate Cancer Gene Soon To Be Available on Saturday January 03, @05:13AM
That really WAS soon!
The case of the British couple who had their daughter tested for the presence of mutant breast cancer genes is not representative of all genetic testing for breast cancer genes. This case involves pre-implantation diagnosis, and if the child was carrying the mutant alleles for the breast cancer genes, the only option to avoid having a child carrying the mutations would have been to abort the foetus (or carry it to term, but knowing that it carried the mutant alleles). But this isn't the usual way of testing for mutations in those genes - I could go and be tested tomorrow, and from what I understand it would involve a blood sample (see for details on testing for the breast cancer genes). Granted, a saliva test would be easier than a blood test, but all in all they're both far easier than the pre-implantation diagnosis carried out in the referenced articles (Slashdot article and the orignal article from the BBC).
Amenacier
Example; if someone said a watermelon is blue on the inside, but turns red when you cut it open, how could you prove them wrong? How could they prove they're right?
By using your brain. In quantum physics they had this exact problem. And they hated it. ;)
Maybe you remember the double-slit experiment, where light from one light source creates an interference pattern instead of the previously expected two lines. Every time the scientist tried to measure where the photons went trough, the interference went away. There was no way to measure it and retain the pattern. So they got very very smart and tricked physics with its own methods.
They used the strange effect of quantum entanglement. Before sending the photons trough the two slits, they entangled the photons with another photon. Then they sent both down a similar double-slit set-up... with one small difference. They measured the entangled photon! And because they never measured the actual photon, the interference survived!
But because two entangled particles share the same quantum state, they could measure the entangled photon and get the same data as for the actual photon.
I'm sorry, I did not read the rest of your comment after countering your base assumption. It was too long anyway. ;)
Any sufficiently advanced intelligence is indistinguishable from stupidity.
There isn't.
There are several problems with gene therapy, or, in your example, somatic gene therapy, as we call this technique. To summarize them: The problem is to "do it right". Granted, some cells are easier to target with specific virii, and some erroneous genes are easier to displace than others. But there's always an error margin in such a therapy, there always will be side-effects. And when talking about modifying genes of multicellular organisms, the most common side-effect is this: cancer. You will at some point of the therapy introduce dis-regulation of certain genes and thus you will increase the risk of cancer.
Gene therapy is not ready yet for prime time, the benefits don't outweigh the faults we introduce (some extreme cases of genetic disorders are possible exceptions).
Well, that's why some disease genes (like the one responsible for sickle-cell anemia) do exist at all: They provide for some positive side-effects.
If medically indicated, I'd have not much problems with that. But ...
The negative aspects far outweigh the benefits if you just change your genes for the sake of it.
And, remember: Gene therapy sounds great in the media because scientists need funding.
Disclosure:
IAAMB (molecular biologist)
Carrying the mutant genes in question (such as the ones that give a predisposition to breast cancer or prostate cancer) is not a sure sign that you will actually contract that cancer. Virii are part of a biological system, and as such are not immune from natural forces such as mutation rates - while DNA replication and other cellular mechanisms are designed to maintain the integrity of the genetic information, the processes are not perfect. So is it worth taking a risk to fix an allele that predisposes you to cancer with a treatment that may induce cancer itself?
Amenacier
Hi I'm doing a study of why sometimes otherwise smart people believe silly things. Plz contact me - you seem like the perfect example.
Control is an illusion, order our comforting lie. From chaos, through chaos, into chaos we fly
And masturbate a lot. http://news.bbc.co.uk/1/hi/health/3072021.stm
This is an issue for every man over 65 or so. Its an issue for a some men between 50 and 65, and for very few under 50. But if you have a father, its going to be an issue for him.
The problem is that you can diagnose the condition fairly well. You can do PSA tests, particularly free PSA, and you can take biopsies. The thing you can't do is predict very well from these tests how vigorous the cancer is. Now, this might not matter if the treatments were fairly benign, and if they were highly sucessful. But they are not. The side effects of all physical treatments, including radiation, are considerable and very unpleasant in a majority of cases.
They are better than dying of course - death from metastized prostate cancer is very painful and unpleasant. But the problem is, if your cancer is discovered by routine PSA screeing, you don't then know whether what has been discovered is a cancer that you will live with until 90 without noticing, or if its one which if not treated will kill you in a few years. Almost all men die with prostate cancer. Few die of it.
This gives rise to the problem about screening. It could be that the effects of screening will simply be to treat more people who would be better off untreated. So the discovery of a genetic marker is potentially a great step forward. If it can pick people to screen who are really at risk of a galloping form, it will lead to more treatment of those who would benefit, and less of those who don't really need it.
For what it is worth, I had to research this question for someone a few years ago. I came to the conclusion that surgery and radiation and cryo are all dubious in terms of efficacy and very poor in terms of side effects - impotence, incontinence, in the case of radiation, collateral damage to other tissue. My own conclusion was that conformal radiation is the best of the physical measures, but probably the best overall is intermittent hormone ablation.
The cancer grows in the presence of testosterone. If this is blocked, either by the administration of testosterone blocking hormones, or by physical castration, the cancer will cease to grow and will shrink. PSA will fall. Unfortunately after a while, the cancer becomes hormone refractory - it learns to grow in the absence of hormone. This is why hormonal treatments are only temporary. However, if you then turn on testosterone again, the hormone supposedly will be unable to handle it, and will shrink again.
This is what I would do if afflicted. But I know of no studies showing this works, and I've never met anyone who has undergone it. Apparently what you do is total hormone blockade with drugs for about a year or 15 months, then stop and let testosterone production resume. As soon as PSA rises again, go back on the drugs. Its probably very risky. But the alternatives are not very appetizing either.
This is not like appendicitis. Its one of those things where no alternative is good, and what to do depends on your judgment of risks and rewards. Very tough. My friend by the way had a biopsy. He was free of cancer. But the act of taking the biopsy under general anaesthetic was not risk free, and produced a total urinary blockage. He was then permanently catheterized, which gradually took a toll on him because of repeated infections, and he ended up dying with MRSA of a failing heart. Whether to find out for sure if you have it is not a simple decision.
This touches on a significant male rights issue that the press refuse to report on. Male cancers lag far behind the cancers that are specific to women in terms of awareness and research. Few people even know that prostate cancer is actually more common than breast cancer. More men than women die of cancer each year.
Despite this, feminists would probably argue that they are campaigning in order to raise awareness of female cancers. A woman might mention to her colleagues that she is going to have a lump in her breast examined. Most men would find it difficult to raise the subject of a lump in their testicles when chatting with their closest friend.
Michael Reed, freelance tech writer.