What causes mouth cancer?

Mouth cancer is closely linked to certain lifestyle habits. For example, about 80% of people who develop mouth cancer (also called oral cancer) use tobacco, according to the American Cancer Society. Both smokers and people who chew tobacco are at high risk for this kind of  cancer. Drinking alcohol also seems to increase your chances of getting mouth cancer. The more you smoke and drink, the greater your risk. (Men smoke and drink more than women do, which is probably why men are twice as likely develop oral cancer.) Spending a lot of unprotected time in the sun increases your odds of lip cancer, a form or oral cancer. Recent research also suggests that exposure to the human papillomavirus (HPV) through oral sex also boosts your risk.

Mouth cancer is caused by the mutation of DNA in healthy cells. Over time, cancer cells grow while healthy cells die. It is unknown exactly what causes this, though tobacco and alcohol may increase risk.