Characterization of bacterial profile in oral squamous cell carcinoma patients

Each year, 30,000 Americans are diagnosed with oral cancer; the disease kills one person every hour in the U.S. The 5-year survival rate (50%) can be improved by early detection followed by appropriate treatment. Use of tobacco and alcohol are the major risk factor for oral cancer. Other possible risk factors include viral infections and poor oral hygiene. The involvement of bacteria has recently received some attention and there is increasing evidence to suggest that studies on the microbial biome are warranted. Objectives: To evaluate the difference in oral microbial diversity between oral squamous cell carcinoma (OSCC), dysplasia and normal non-cancerous individuals by cultivation-independent methods including denaturing gradient gel electrophoresis (DGGE) and 16S rDNA sequence analysis. Methods: Saliva samples were collected from 11 individuals (OSCC=3; dysplasia=3; control=5) aged 21 and older. Total bacterial DNA was extracted and aliquots were amplified using a set of universal 16S rDNA sequence primers. DGGE was performed with the Bio-Rad DCode System. Results: Initial results indicated that the bacterial profiles were different in OSCC and, dysplasia as compared to the controls. The normal control samples had similar profiles. The dysplasia samples had a different bacterial profile than the controls and were more similar to the OSCC profile. The lane comparison indicated a shift in the bacterial profiles in OSCC and dysplasia and indicated a clear distribution of phylotypes between the three groups. Some phylotypes present in normal controls were absent in both dysplasia and OSCC, while other phylotypes were present only in OSCC. Conclusion: Initial studies demonstrated that there may be a shift in the bacterial profile in OSCC and dysplasia as compared to healthy controls. The significance of this change in bacterial profile is yet to be determined.

This work was supported by NIDCR Grant U54-DE14257 and NYU Faculty Research Funds.