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In oral cavity chronic inflammation has been observed at various stages of oral squamous cell carcinomas (OSCC). This inflammation could result from persistent mucosal or epithelial cell colonization by microorganisms. There is an increasing evidence of the involvement of oral bacteria in inflammation and warrant further studies on the association of bacteria in the progression of OSCC. The objective of this study was to evaluate the diversity and relative abundance of bacteria in the saliva of subjects with OSCC. Using 454 parallel DNA sequencing, ~58,000 PCR amplicons that span the V4-V5 hypervariable region of ribosomal RNAs from 5 subjects were sequenced. Members of 8 phyla (divisions) of bacteria were detected. The majority of classified sequences belonged to phyla, Firmicutes (45%) and Bacteroidetes (25%). Further, a total of 52 different genera containing approximately 860 (16.51%) known species were identified, 1077 (67%) sequences belonged to various uncultured bacteria or unclassified group. The species diversity estimates obtained with abundance-based coverage estimators (ACE) and Chao1 were greater than published analyses of other microbial profiles from the oral cavity. Fifteen unique phylotypes were present in all three OSCC subjects.

Objective-Risks associated with smoking and drinking are not necessarily constant over the multistage pathway to oral cancer. We investigated whether smoking and drinking patterns differ for persons with oral cancer (OC) relative to those with oral epithelial dysplasia (OED), a precancerous condition.Methods-Incident cases of OC and OED were interviewed using a questionnaire containing questions on smoking and drinking. Odds ratios (ORs) compared the odds of smoking and drinking among persons with OC relative to OED.Results-No adjusted ORs for smoking achieved statistical significance; however, most were <1.0. The odds of OC relative to OED increased with drinking level; the adjusted OR for 19+ drinks/week was 3.03 (1.56-5.87). Age drinking began and years of drinking were not notably different for OC and OED cases; a higher proportion of OC cases reported discontinuing alcohol for 9+ years before diagnosis. Conclusions-The relationship between smoking and OED was at least as strong as that for smoking and OC, suggesting that smoking may have its greatest impact on oral carcinogenesis prior

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