[ackfoo]

I applaud your motivation, and I agree with your suggestion, but that's not where most cancer comes from. Most cancer arises out of a random failure of the mechanisms underlying apoptosis.

Random mutation rates are linked to rates of cell division. There is an error every x number of times a cell divides. The faster cells divide (say, because of inflammation caused by cigarette smoke), the greater the risk of a random mutation that will disable the normal mechanisms of cell death.

Environmental mutagens and carcinogens play a part by damaging DNA or increasing cell division rates (asbestos, for example, which destroys immune cells come to engulf the invader, leading to a cycle of cell damage) but they are only a tiny part of the picture.

Cancer is caused by math, in a very real sense. Mutation rates * cell division rates = risk of cancer. You can absolutely get cancer without any adverse environmental exposure, which is why some children get cancer very early on--genetic factors increase risk.

The universe is chaotic. There is often no reason for what happens to an individual. It's just random chance. Man's search for meaning is often futile.