Flossing, Brushing May Reduce Cancer Risk

Despite declining use of tobacco products – historically the # 1 cause of oral cancers – cancer of the tongue, the tonsils and the back of the throat is on the rise. More than 30,000 Americans are diagnosed with new cases of oral cancer each year.

One of the culprits is thought to be human papillomavirus or HPV, a virus definitively linked to cervical cancer in women. While a vaccine against HPV now exists, thanks in part to University of Rochester Medical Center colleagues William Bonnez, Richard Reichman, and Robert Rose, tens of millions of people are already infected with HPV, the most common sexually transmitted disease. Many scientists believe HPV, and the growing practice of oral sex, are behind the increasing incidence of oral cancer.

My laboratory is looking at just how HPV contributes to oral cancer. It’s possible that pockets of gum inflammation and tissue destruction in the mouth provide a reservoir for HPV, which the virus uses to infect nearby tissue. Other teams are studying the link as well. Recently in the journal Archives of Otolaryngology, scientists describe a possible association between oral inflammatory disease – chronic periodontitis or gum disease – and HPV infection in patients with head and neck cancers.

Our “oral flora” – the mix of bacteria in the mouth – is crucial for our oral health. More than 800 types of bacteria call our oral cavity their home. Our lab is taking a look at how they live together, which ones are friendly or “commensal,” which ones might be harmful, and what happens to our health when the usual mix changes. Working with Sean Newlands, Paul Van der Sloot and Matthew Miller in the Department of Otolaryngology, we are investigating the mix of bacteria in tumors from patients, and comparing the findings to those in patients who do not have cancer.

While it’s well known that some viruses, like HPV, have a role in the development of some types of cancer, we’re investigating whether the bacteria in our mouths play a role as well. Currently we are pursuing some exciting leads regarding the presence of a bacterium in oral tumors that is normally considered friendly.

A possible role for gum disease in the process is fascinating but also concerning, since at some point in their lives, more than half of all U.S. adults will be affected by gum disease. It’s possible that gum disease will be seen some day as a risk factor for HPV infection and may provide a diagnostic marker for possible development of or cancer.

Prevention of oral inflammatory disease may be an effective approach for preventing the acquisition of HPV and subsequent infection. Practicing good oral health, especially brushing and flossing one’s teeth regularly, are easy steps to prevent gum disease and maintain a healthy mix of bacteria in the mouth and throat.

Steven Gill, Ph.D., is associate professor of Microbiology and Immunology and a scientist in the Center for Oral Biology. He has been studying microbes for more than 25 years and is on the trail of vancomycin-resistant Staphylococcus aureus, which is even deadlier than methicillin-resistant Staphylococcus aureus or MRSA.