Sunday, October 25, 2009

Is skin cancer a product of our evolutionary misjudgement?

Why don't animals get skin cancer? They have no clothes on to protect them from radiation. Is their fur protecting them?
Lately I have started to think that millions of years ago mankind did not have problems with radiation from the Sun but as we started wearing clothes to protect us from the cold, we lost the body hair and an eventually our immunity to the radiation was reduced to a point where we are now very vulnerable. Clothes are as unnatural as artificial sugar.
Incidentally, darker people in Africa have less cases of skin cancer and I attribute that to the fact that they have been wearing less clothing than the rest of the world population and their immunity has not been been affected as much, at least so far.
Any thoughts?
Answer:
Animals do get skin cancer, as a previous poster noted, but it's either not treated or not commonly discussed (not really a great cocktail party topic!). Part of the reason that skin cancer seems so prevalent lately is that people are diagnosed more often now and there is more to diagnose. Our grandparent's generation spent very little time sunbathing and when they did, their suits were very concealing. People expose more skin more often now. The increasing incidence of skin CA in younger people supports this.
As for Africans, their increased pigment protects them from the dangerous UV rays, preventing them from penatrating into the cell and damaging the DNA, causing the mutation that results in skin CA. The darker your "natural" skin tone, the less risk you have. However, Africans still do get and die from skin CA.
Most animals do.When you speak of Evolution -- speak for yourself...
Nice thought, but there's a problem. Animals get skin cancer it's just not treated. You are correct in your assumption that fur blocks some radiation (just look at a guy who has shaved his head recently, the skin is all white - less exposure) so there is some basis to your conclusion. The problem is that the sun, while a factor in cancer resulting from damaged skin, is not the only source of impact to someones disposition to getting cancer. Cancer is a part of our existence, and the main reason we, as a species, will never be able to live forever, even as our medicine improves. To simplify it, think of cancer as a computer glitch. Any computer, left to run long enough, will experience a glitch, the DNA in your cells acts like a "computer" and given a long enough time-line will eventually make a mistake. These "mistakes" are the basis of what we call cancer. Some people have a computer they use in a dirty dusty shop (like a human smoker) that never has a problem, some have a computer in a climate-controlled office (like someone who stays out of the sun, minimizes exposure to asbestos and other chemicals) and crashes (gets cancer) anyway.Losing our hair as a species has increased our exposure to one of the catalysts of cancer, but it wasn't an immunity.Sun screen for the win!Keep thinking about science, it just might save our species someday!

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