The oral microbial community (the microbiota), is centrally related to nutrition, metabolism, immunity, inflammation, and endocrine balance. Cigarette smoking is associated with serious health outcomes including cancer, cardiovascular disease and chronic lung disease. However, little is known about the relationship between cigarette smoking, oral microbiota and tobacco-related health outcomes. Microbiotas in the different sites of the same oral cavity vary widely. Recent studies indicated that the difference in microbial profiles between buccal mucosa and gingival plaque is as distinct as the difference between tongue and stool. To date, knowledge about the effect of smoking on oral microbiotas is lacking. As an initial step toward understanding the role of the oral microbiota in smoking-related health outcomes, we propose a pilot study to evaluate the effects of cigarette smoking on the microbiotas in buccal rinse obtained from the oral cavity and across 8 different oral cavity sites/niches (saliva, swabs from tongue dorsum, hard palate, buccal mucosa, keratinized gingiva, palatine tonsils, supragingival plaque, subgingival plaque). We will seek to recruit up to 50 volunteers through the Eastman Dental General Dentistry Clinic, Rochester, NY, including 25 current smokers with \> 5 years of smoking history and 25 never smokers as a comparison group. Age-group, gender, and race (Caucasian/African- American) will be matched for the two groups. In each subject, the buccal cell (mouthwash) collection will be collected according to the PLCO buccal cell collection protocol. In addition, collections across 8 different oral cavity sites will be done using a protocol developed for the Human Microbiome Project. These 9 collections will be used for high throughput sequencing of 16S rRNA microbial genes at the Institute of Genome Sciences, University of Maryland School of Medicine. The findings will provide information about the effect of smoking on microbial taxa composition and relative abundance at each collection site. This pilot study will demonstrate the effects of smoking on oral microbiotas across different oral cavity sites and will also demonstrate which oral collection site is most promising for the detailed study about cigarette smoking and oral microbiota. In addition, the data collected will provide a validation framework to use the PLCO buccal specimens for large-scale studies. The information about the validity of using PLCO buccal cell collection will be an invaluable asset for further large scale studies of the microbiota and cancer risk. We will also be able to investigate if there is any taxonomy or microbial diversity difference between heavy smokers and never-smokers. This pilot study will provide essential information about collection, design and analyses that will enable further studies of the relationships between cigarette smoking, the oral microbiome and tobacco-related cancers.

Under an Amendment, the participants will be contacted to provide another set of oral swabs and mouthwash samples. The goal is to examine the stability or oral microbiota in 3-6 months and confirm the results based on the first time point. The collection methods, assays and analyses will be analogous to those performed previously.