oral and liver cancers are the big ones, but again it is a quantity issue. these cancers are most commonly in alcoholics, but obviously carcinogeic potential is there.And smokers, one would think.
A very simple way of thinking abut carcinogenic agents goes something like this: The agent irritates and damages the cell, including the cell's DNA. when the DNA is damaged one of two things can happen: the cell can repair it back to normal or a mutation can occur. if the cell gets enough mutations it no longer responds to the growth regulating factors in the body and it grows out of control (this is what cancer is). one mutation isn't enough to do it, it takes multiple "hits" so the more exposure you have to an agent the greater your chances are of getting a mutation. but don't despair, the body is very good at repairing itself and will make the right DNA repair 99.99% of the time. plus the mutations have to occur in genes related to cell growth (85% of your DNA does nothing -mutations there don't matter!).
say you sunburn a billion cells, maybe 1,000 will pick up a mutation, but only 150 or so will have a mutation in an important part of the DNA. if you get another sunburn, the chances are very, very small that one of these cells gets a critical mutation again, but everytime you get a sunburn, your chances go up. this is why a 5 yearold with one sunburn doesn't get melanoma, but a 40 year old surfer will (same with alcohol/alcoholics).
posted by caddis at 7:50 AM on June 16, 2005