I do volunteer work with cancer patients - cancer is insidious. You can do everything "right" and it works its ways in in the most horrid of ways. I strongly believe genetics plays a huge role - surely with all the money that's gone into cancer research, it shouldn't be the dreaded disease it is. Although there have been many advances, I feel a couple of the biggest culprits in contributing to the disease are smoking, in particular, and physical inactivity. Yes, too much sun obviously isn't good for you or your skin, but every time I walk by a smoker, I want to snuff out their cigarettes and yell how disgusting and dangerous, not to mention unpleasant, it is. It's the worst thing you can do to your body, and others.