Cancer Causing Viruses

September 30, 2009 2:10 PM

Paul Ewald, an evolutionary biologist at University of Louisville in Kentucky states his conviction, in one interview with Discover Magazine that, that by 2050 the human species will have found that between 80% and as high as 95% of cancers are caused by viruses.

from Discovery Magazine Article:

Viruses push cells to the brink; additional mutations from genetic defects or the environment are needed for full-blown cancer. Keep in mind that the vast majority of mutating agents provoke cells to stop functioning or to die, meaning there is no chance for those mutations to cause cancer. Without an infection, the few mutated cells that could potentially cause cancer stop proliferating after several divisions. But infected cells can reach such high numbers that the progression to cancer is not terminated by the many mutations that kill the cells or make them nonfunctional. The small percentage that are cancer-causing can continue to proliferate.

posted by mdpatrick (19 comments total)

an evolutionary biologist...in Kentucky

Red state cracks aside, I've heard this echoed by several scientists before. I think the advent of high-throughput sequencing may help decide this one way or another...
posted by greatgefilte at 2:40 PM on September 30

I've been discussing this with my vets for years. Odd how vets keep on this stuff so much more than human doctors.
posted by dilettante at 2:56 PM on September 30

Wiki: Oncovirus

Don't read it if you want to sleep well tonight.
posted by seanmpuckett at 3:04 PM on September 30

The assertion that most cancers are sexually-transmitted is fascinating to me.
posted by hippybear at 3:04 PM on September 30

Great, I'm probably going to die of cancer....
posted by dragonette1 at 3:32 PM on September 30

This is, 1. Old news. 2. Probably true. 3. I would venture to predict that many more cancers and other diseases will prove to be sexually transmitted.
posted by Faze at 3:55 PM on September 30

'Nuns, Virgins, and Spinsters'. Rigoni-Stern and Cervical Cancer Revisited: "As we cannot be expected to know the intimate past history of all nuns, none should be considered immune to cervical malignancy."
posted by benzenedream at 4:19 PM on September 30

Interesting. My thoughts immediately went to finding the cancer rates of sex workers, but I'm guessing they're involved in other risky behavior compared to the general population and you'd have crufty data. A quick google on celibate priests yields some interesting results:

"The death certificates of 1006 (95%) priests were reviewed. Of these 156 deaths were attributable to malignant neoplasms. Clerics experienced mortality ratios of 15% less for all causes of death and 30% less for cancer mortality, given mortality patterns among New York State white males of comparable ages. Twelve deaths from prostatic cancer were observed while 19.8 were expected. This represents a mortality experience significantly less than that of the general noncelibate population. Lower mortality ratios were found also for cancers of the lung, colo-rectum, and stomach. Higher mortality ratios were found for malignant melanoma and unspecified respiratory organs."

Bernadino Ramazzini conducted the first epidemiological cancer study on nuns in the 17th c., finding lower instances of ovarian cancer but higher instances of breast cancer, which he attributed, ironically, to celibacy. Apparently not having children is still a risk factor for breast factor.

I began wondering how long-lived trees don't get cancer and then began to wonder if long-lived and large mammals like whales have cancer. It appears I stumbled upon "Peto's paradox", ". In larger organisms, tumors need more time to reach lethal size, so hypertumors have more time to evolve. So, in large organisms, cancer may be more common and less lethal."
posted by geoff. at 4:20 PM on September 30 [1 favorite]

huh, I always thought that nuns lived forever because they did not have to put up with a husband and children and in-laws.
posted by Cranberry at 4:49 PM on September 30

I'll let Alex Chilton speak for me on this one.
posted by digitalprimate at 5:42 PM on September 30

(On review, um, sorry, lyrics NSFW on that one!)
posted by digitalprimate at 5:46 PM on September 30

I've always wondered about this myself, but have never had the time to go digging in the literature to see if anyone in the field thought the same thing and why... my guess, based solely on what research I have read over the years is that it will turn out that viruses and a strong genetic component (ie, susceptibility to the virus) are at the root of cancers.
posted by Zinger at 5:51 PM on September 30

Plague Time by Ewald was extremely interesting. In retrospect, it's going to seem really, really dumb that the medical community didn't adopt the fundamental theory of biology sooner...
posted by DU at 5:57 PM on September 30

If ya call that living amirite:

Britain's oldest virgin has revealed the secret of her longevity on the eve of her 105th birthday - no sex.

Meanwhile the other big insight in longevity research right now is calorie restriction.

Eating makes you die. Sex makes you die. I can't wait for future longevity discoveries, such as 'sitting motionless in the middle of a room with all the lights off for 17 hours a day increases lifespan by 16%' and 'petting kittens causes lethal brain damage'.

Oh wait, that last one is already true. Fuuuuuuuuuuuu-
posted by dgaicun at 9:15 PM on September 30 [1 favorite]

A quick google on celibate priests yields some interesting results:

Geoff, that is interesting, but is the population average a good control group? Priest is a high status job, and it looks like protestant clergy, who do have sex, have even lower mortality than celibate Catholics.
posted by dgaicun at 9:30 PM on September 30 [1 favorite]

In retrospect, it's going to seem really, really dumb that the medical community didn't adopt the fundamental theory of biology sooner...

There are plenty of biomedical researchers looking at cancer and everything else in biology from an evolutionary perspective. Your family doctor may not give it much thought, but that's because they're like mechanics: You show up with a problem, they figure out how to fix it. Researchers (including many MDs) are the ones with the time to dig deeper into the mechanisms.

by 2050 the human species will have found that between 80% and as high as 95% of cancers are caused by viruses.

As someone who studies cancer from a bioinformatics perspective, I'd take him up on that bet (LongBets.org anyone?). For one, there's a huge difference between contributing and causative. For another, there are a preponderance of other ways to accumulate mutations. When you consider the number of replicative cycles we go through with non-perfect machinery, and the sheer number of mutagens we're exposed to every day, it's amazing that we don't all get cancer sooner.

Can viruses contribute to cancer? Absolutely. Can they explain 95% percent of them? I doubt it.
posted by chrisamiller at 6:59 PM on October 1 [1 favorite]

If you include mutations in all virally affected DNA then yeah sure, but that's only because most of our 30,000 genes come already virally affected. But this guy is talking about live viruses not inherited and otherwise useful viral genomic data. However, assuming this, just the sheer amount of people who die from oncogenically related Breast cancer show that he is wearing his ass for a hat

I would make sure you define that bet carefully chrismiller.
posted by Blasdelb at 11:42 AM on October 2

I used to do virology and I think that viruses are under appreciated as contributing factors to human disease, but don't believe this guy's estimate. Viral oncology has been around for decades though and there has been plenty of investigation into bystander effects caused by viral induction of cellular proliferation (HHV-6 and multiple myeloma, for instance).

I agree with chrisamiller though - 80-95% is assuming that our bodies are extremely good at not getting cancer (even in old age where there is no reproductive selection pressure NOT to get cancer) and viruses are extremely good at getting to and causing cancer in all tissues. Cells that are undergoing complicated division many times over our lifetime have plenty of chances to evolve into tumor cells - any cell that mutates to replicate faster or mutate more quickly will soon be able to ratchet up its mutations to become a rather complicated tumor cell. A good counterexample would be ovarian cancer - I'm unaware of ovary-targeting viruses.
posted by benzenedream at 3:00 PM on October 2

If you include mutations in all virally affected DNA then yeah sure, but that's only because most of our 30,000 genes come already virally affected. But this guy is talking about live viruses not inherited and otherwise useful viral genomic data.

Yeah, I thought about all the viral remnants in our genome, and figured that some bad reporting had misconstrued the guy's words. Then I clicked through, and it appears to be a verbatim quote - he really believes this (or at least is saying so to drum up publicity).

I used to do virology and I think that viruses are under appreciated as contributing factors to human disease

I won't argue with you there. Hell, if the guy had said that viruses will be found to play a part in two dozen kinds of cancer, I wouldn't have blinked an eye. Shoot - look at HPV alone, and you could make a case for some other viral mechanisms that aid in oncogenesis. But viruses being causative of 95%?! Talk about overselling...
posted by chrisamiller at 8:35 PM on October 2