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Comment by lifeisstillgood | Hacker News Reader

OK, this is a silly question but I have to ask

Is there any likelihood that measles, or a similar virus we have held at bay with vaccination, was actively fighting cancer 200 years ago, thus pushing up the incident rates that apparently have gone up and dismissed with "well we weren't dying of cancer because we were dying of $INSERT_DISEASE_HERE"

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It is not a silly question. We can put it through the paces. The question you are getting at is, "Did measles evolve to keep cancer at bay?" Or stated in another way, "Did it evolve because it was keeping cancer at bay?" The 2nd question is more attuned to our understanding of evolution.

For this to be the case, cancer must have been killing a significant number of people before they reached the reproductive age. However, we know cancer rears it's face well passed people have reached reproductive age. For women, breast cancer the most common of them all becomes rampant post-menopause.

With this view point, it seems unlikely that measles was an evolved response to cancer. Because, this has been a hand waving argument it has not addressed the ratios required for an evolutionary response, i.e Is it possible that cancer was killing enough (however small) prepubescents and that gave measles a chance to evolve?

Or, could it be that there was a way milder measles like virus that people acquired (like the common cold virus) and lived with henceforth and that protected them from cancer?

There are many interesting questions that come up.

The viruses didn't have to evolve specifically to fight, it could have been a side effect. For example, maybe cancer cells make better viral hosts because of their unchecked metabolism. So the virus evolves to exploit cancer cells first, killing them in the process. Here the virus "cures" cancer by accident, with no interest in the fact that it extends the life of their host.

I'm not saying this is likely, I'm just pointing out that your restatement of the question is a lot more narrow than the original question.

That was by intention. Head on, the original question is less penetrable. The restatement is meant to emphasize that a symbiotic relationship between the host and the virus could drive the evolution. Cancer -- bad for host, virus takes care of cancer for selfish reason, host lives long giving virus opportunity to spread. Along this line, your example gives a possible immediate attraction for the virus. It is the immediate attractions that start off the relationships, to disastrous, neutral or beneficial long term ends.

It is even possible that different viruses could be fighting each other to get a piece of our cancer. Interesting stuff!

Ask a dumb question, get a great thread out of it.

Thanks

> For this to be the case, cancer must have been killing a significant number of people before they reached the reproductive age.

Evolutionary forces are still in play for people past their reproductive age, though admittedly in a much less direct way. A person that lives long enough to help care for their grandchildren will be more likely to have some of their genes survive.

Yes, particularly in a hunter-gatherer society (which all of us were until quite recently in evolutionary terms). In addition to caring for grandchildren, there's also the wisdom of age. It's only in recent generations that things have started changing so fast that this is devalued. For a long, long time having grandpa or grandma around to tell you where you could still find water in a once-in-a-generation severe drought, or what other things you could eat when the herds of food animals didn't show up that year, was very useful.

Looking at it another way, if old people weren't useful evolution would not have produced humans with such long lifespans after reproductive age (since the old people are consuming resources, populations where individuals died off shortly after the kids were autonomous would have had an advantage).

As I read it, in this case it's a specially modified version of measles that's used, not "vanilla" measles. Interestingly, the washington post write up also suggests that if the user had resistance to measles, another virus would have to be used.

Thank you, just there seems to be a lot of unanswered questions in this area. Which I guess is why its interesting.

cheers

This is what makes me skeptical about the possibility of the virus offering general protection. We have this immune system that provides us with protection from infection if we've already had measles, to the point that it will protect the cancer too. That means that unless you get measles for the first time while you happen to have cancer, it's not going to help you. So I suspect this didn't actually come up enough in nature to have a real impact.

It seems more likely that simply dying before getting old enough to develop cancer is the reason there was less incidence of cancer centuries ago.

True. For multiple myeloma, the average age at diagnosis is 65 years. However, there are more and more young patients each year. The youngest person I have seen was 18 years old.

They altered the virus to kill cancer cells instead of kids which is what measles does by the truckload in Pakistan and India :/

Fear not, I was in no way suggesting we rollback centuries of vaccination in case it helps late-stage cancer patients.

Rolling out vaccination is a Good Thing.

No your question is quite relevant, and a good one.

There is some research along similar lines regarding exposure to certain parasites and disease.

http://www.scientificamerican.com/article/helminthic-therapy...

http://www.bbc.com/future/story/20130422-feeling-ill-swallow...

It's unlikely, as most vaccine-preventable infections were diseases of childhood, so any selective pressure they put on other things in your body would take place well before most cancers develop.

It is however mathematically certain that the prevention of deaths from infectious diseases will drive up rates of death from other causes, as we have to die of something - the only question is what.

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