The younger of Blanche's brothers is a type 2 diabetic and a heavy smoker. Whenever anyone tries to suggest that he give up smoking for any reason he counters with how smoking is not related to cancer and how if you're going to get cancer you'll get it no matter what you do because cancer is all genetic. No matter what you tell him about life expectancy after quitting he'll think of something that contradicts it. He keeps on at this until the other person is weary of the argument.
Denial isn't just a river in Egypt.
Well, to a certain extent, he's right. All cancer is genetic . . . but it's not always inherited. Every cancer involves some sort of genetic mutation - caused by random chance, a carcinogen, a virus, etc. Also, I have heard that all adults have had a cancer but that normally one's body is able to remove the cancerous cell(s) before it's a problem. However, while some mutations just happen outside of our control, the idea is not to induce as few mutations as possible. So . . . stop smoking.