Influence of Smoking on Microbial Diversity

Head and neck cancers will kill 8,000 people every year in the United States, in addition to affecting 41,000 new cases. While treatment for oral cancer typically include a combination of surgery, radiation, and chemotherapy, these methods may cause many deleterious effects to the patient and can encourage some to forgo treatment until it is too late and the cancer is in an incurable, advanced stage. As pro-carcinogens continue to become more common, as in tobacco smoke, environmental factors and food, risk factors for head and neck and other cancers rise. There is a clear need to identify patients at highest risk for cancer in order to reduce their threat and begin a preventative treatment as quickly as possible. Surrogate markers for toxic oral bacteria, such as tooth loss, and their link to different cancers suggest that oral bacteria have effects on oral and other cancer rates and additional diseases. Objective: We propose to examine bacteria at different sites in the oral cavity to determine if there are bacteria species and genera associated with tobacco exposure and periodontitis. Methods: We have sampled bacteria on healthy and diseased gingival surfaces, healthy and diseased sulvi and the oropharynx of n=24 subjects. Results: The diversity of the oral microbiome in the tongue and oropharynx were found to increase in subjects with periodontal disease compared to healthy controls. Conversely, the diversity decreased in these subjects with periodontal disease in smokers versus non-smokers. Qualitatively, dysbiosis is suggested to increase in the face of both periodontal disease and smoking. These results provide novel mechanisms into the genesis of oral cancer in patients with periodontal disease and/or smockers.