Cancer, many biologists aruge argue, is an evolutionary disease. It is a burden of being multicellular, and a threat against which natural selection has only managed mediocre defenses. Making matters worse, cancer cells can borrow highly evolved genes for their own deadly purposes. And even within a single tumor, cancer cells get nastier through natural selection.
I've been following the study of evolution and cancer for some time now, and have blogged on the Loom about it here, here, and here. But it was a review in Trends in Ecology and Evolution that spurred me to launch a full-blown article. The articles appears in the January issue of Scientific American, and you can read it here.
Scientific American also runs a podcast each week, and you can listen to an interview with me about the article here.
It's a fast-moving field now--another big review appeared in Nature Reviews Cancer after my article was off at the printer. As I write in the article, we're at an early stage right now, when evolutionary biologists and cancer biologists eye each other warily, unsure that the other side understands the nuances of their own field. So I'm eager to see where things are going to go.
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Interesting stuff. Hopefully there will be a fix one day. But, just had to point out: "argue."
Good article Carl. Working as a molecular geneticist in cancer research I have to admit that the mechanistics of evolutionary theory have not been at the forefront of thinking in this field until very recently. That said the genome project and the associated explosion of knowledge regarding expression and the accurate determination of critical intracellular pathways altered in cancers are having a big effect on how we approach the subject. What is becoming clear is that there seems to be a limited number of biological pathways affected in cancer - such as those of MYC or P53, providing hope for future therapeutic measures targeting cells that have these particular malignancy inducing alterations. Extending the evolutionary approach in cancer to incorporating the relatively more recent terms of the selfish (onco-) gene or the extended (tumor) phenotype - through the release of cytokines or angiogenic factors - obviously has a lot of potential to aid in the understanding of this disease.
What's the deal with this guy?
RPM--James Graham, who left the comment on your site, wrote a book about cancer and evolution in 1992, which has been cited by some of the scientists now publishing work on the subject. The idea that rapid evolution of certain genes may lead to pediatric cancers is just one of a number of ideas that are being investigated now in the intersection of cancer and evolution.
As a cancer survivor, I was amazed how empirical chemotherapy was. When I would ask my oncologist why he was going with this particular drug in the cocktail, he would shake his head and say, "It works". When I would press further--what are the mechanisms?, are they complementary?--he would say "this combination leads to higher survivorship", and give me a look akin to "that's what you want, right?".
Who was I to argue with that?
Life struck a Faustian bargain with cellular respiration. Compared to anaerobic respiration, we can, through some amazing chemistry and lots of oxygen, crank out a lot more ATP for every molecule of glucose. But at what cost? All those free radicals.....
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So, a high rate of change in genes may in itself interfere with optimizing them against cancer, by giving the evolutionary process a "moving target" to optimize? I was wondering that as I was reading your article (which was very good BTW). I suppose it doesn't really matter whether a gene could be well optimized both in its function and against cancer, if evolutionary processes can't find such a solution in the time given.
Carl Zimmer: "This guy" thanks you for noticing.
RPM: As I say on my site and in my book the current explanation (Neo-Darwinism) for the existence and evolution of Bilateria makes no sense unless one postulates the existence of oncogenes in all Bilat somatic cells and the past cancer deaths of uncounted juveniles, a mechanism I call "cancer selection."
A complete theory of animal evolution needs "evo-devo" and "evo-devo" needs "onco".
My idea, which I began working on in 1977, was published in Journal of Theoretical Biology (as letters in 1983 and 1984) noted in Nature (a 1992 review of my book) and cited in Nature Reviews Cancer (Leroi et al in 2003).
Although mine is an idea about evolution it is interesting that while some molecular biologists who focus on cancer find it interesting it continues to be ignored by evolutionists.
I find it amusing how researchers and scientists want to explain away pediatric cancer incidence. Cancer is basically genetic damage. The question being, why are babies and young children experiencing genetic damage? Oh yeah, it's the poisons produced from chemicals of industry that are getting progressively worse. This is the evolution of cancer. Remove the cause, prevent the disease. Commonsense that scientists are immune to, because corporations don't profit from this thinking, and research grants are not awarded for this thinking. I feel scientists and doctors have lost their integrity and credibility. The truth of this is becoming more obvious to the man in the street evry day. Citizens are questioning fluoridation poisons in our water, pesticides in our food and medical treatments that barbaric. Just keep thinking the way you are, and as the truth seeps out, your professions will continue to lose support and respect.
Jeanruss: None of the scientists I've spoken to would claim they are trying to "explain away" pediatric cancer with insights from evolution to serve some corporate master. Obviously the environment plays a major role in the origin of cancer. But the environment interacts with the genes we've inherited. So we have to understand that heritage to understand the full picture of cancer--why, for example, pediatric cancers can be caused by fewer mutations than cancers that are most common in older people.
I enjoyed reading the article in Scientific American, though I didn't even realize you were the author! Thanks for an interesting article!
Enjoyed the article. As a practcing MD I'm more and more surprised the lack teaching about evolution done in medical school and how little natural selection is mentioned during clinical practice. I inform patients the reason why studies show they don't need an ankle wrap for their sprained ankle or three days bedrest for their lumbosacral strain ism probably that ancient humans or bipedal creatures that weren't able to quickly heal minor injuries didn't leave many descendants. And, believe it or not, patients get the point and go home satisfied. So mixing medical practice with evolutionary theory may not only help doctors but their patients to understand disease better.
Two examples of cancer demonstrate the evolutionary aspects quite well:
Sticker's sarcoma is a cancer that is not genetically related to the victim -- it's a cancer from an ancient canine that evolved to become a transmissible disease. Tasmanian devils may have a similar illness.
HeLa cells, cervical cancer cells from a patient in 1951 have evolved to live in a lab. I'd agree with Leigh Van Valen that the HeLa cells are now a separate species, with a different chromosomal number and ecological niche.
Carl. thanks for your excellent article, �Evolved for Cancer,� really brings us up to date. As I look at it, the ultimate of cancer evolution is cachexia where the cancer feeds primarily on glucose.
Glucose is a major weak point of advanced cancer. In 1969 Benade, Hunter and Burke at NCI showed that vitamin C in the form of dehydroascorbate readily enters cancer cells through the glucose tubules, forms hydrogen peroxide and oxidizes cancer cells. Normal cells are not harmed. Clinical confirmation comes from Cameron and Pauling, Hoffer and others. They recommended that vitamin C doses should be continued indefinitely-20 years for example. Their tests show that dehydroascorbate is effective long term instead of short term as is the case with many chemotherapies. Perhaps vitamin C kills only the more dangerous cancer cells while allowing some cancer cells to live. Meanwhile patients live longer and with less pain. Abram Hoffer, Vitamin C and Cancer, has treated 1300 cancer patients with great succes.
Dehydroascorbate may be the ideal chemotherapy.
Better references are in my web site at www.cancertherapies.org. May I send you some hardcopy articles.
Reagan Houston, MS, PE (Professional Engineer in Chemical Engineering)
an idea proposed by an obscure engineer makes good sense to me. Cancerous stem cell has acquired genome from methanogenic and/or methylotrophic bacteria some 2.5 billion years ago during a symbiogenetic evolution when oxzgen started to be manufactured in great quantity to change the terrestrial environment from anaerobic to aerobic. The methogenic and/metylotrophic bacteria were seeking refuge in Palomyxa amoeba, and their symbiogenesis gave the cancer cell the selection advantage in evolution.