The rate of occurrence of oral cancer has risen each year for the last five years, according to the Oral Cancer Foundation, and kills one person every hour. It's something many people associate with tobacco use, but that's an incomplete picture. “Seventy-five percent of people with oral cancer usually have some association with alcohol or tobacco, but that leaves 25 percent that don’t,” says Price. Other possible causes include the human papilloma virus (HPV), which is transmitted to a person’s mouth through oral sex, excessive sun exposure, and a diet low in fruits and vegetables.