Smokeless Tobacco Products (STPs) Harbour Bacterial Populations with Potential for Oral Carcinogenicity.

INTRODUCTION: Smokeless Tobacco Products (STPs) vary significantly in their carcinogenicity, a feature accredited to the variation in the concentrations of carcinogenic chemicals. Tobacco associated bacteria are known to produce Tobacco-specific N-nitrosamines (TSNAs) and hence are determinants of TSNA levels in Tobacco. The primary objective of this study was to conduct a microbiological survey of STPs and to provide a baseline information of the bacterial communities present in the STPs. MATERIALS AND METHODS: The present study analyzed the constituency of microbial communities in 7 different smokeless Tobacco products including four chewable (T1_CW to T4_CW), two snus (T5_Snus and T6_Snus) and one snuff sample (T7_Snuff) using high-throughput sequencing of the 16S rRNA based next generation sequencing. The Tobacco samples were also analyzed for pH and moisture content. Statistical analysis of the data obtained was done using SPSS software version 20. Pearson's Correlation was done to analyze the correlation between pH and moisture content of the Tobacco samples. RESULTS: A total of 11 phyla were identified in all smokeless Tobacco products. A total of 36 classes were identified across all smokeless Tobacco products and bacilli was the predominant class in all the products followed by Actinobacteria and Bacteroidia. In species level, a total of 2369 species were identified across all smokeless Tobacco products. In T1 chewable Tobacco products, predominant species was staphylococcus whereas in T2 and T3, Bacillus subtilis and pumilus were predominant. In T4 chewable Tobacco product, Virgibacillus was predominant followed by halodentrificans, staphylococcus epidermidis. In snus 1 and 2, Bacillus pumilus and subtilis were predominant. In snuff, Bacillus cereus was predominant. Snus products had the highest moisture content (15.4% and 14.3%) compared to the chewable Tobacco and snuff products. The snus products analyzed had alkaline values (pH 8.50 and 8.15) and snuff and chewable Tobacco had acidic values ranging from 5.62 to 6.09. CONCLUSION: The current study demonstrates that ST products differ qualitatively, quantitatively, and in their bacterial composition. There is a possibility that some of these species may contribute to oral carcinogenesis, either by influencing levels of TSNAs or directly inducing chronic inflammation.

Diagnostic Utility of Cytology in Assessment of Ploidy Status in Potentially Malignant Oral Disorders.

INTRODUCTION: Oral leukoplakia, the most common potentially malignant oral disorder (PMOD) may progress to oral squamous cell carcinoma (OSCC). Although, the current standard of care for assessing its malignant potential remains histological examination and assessing the severity of dysplasia, DNA ploidy analysis has been suggested as a surrogate marker to predict the behaviour of PMODs. OBJECTIVES: To detect aneuploidy and to correlate ploidy status with different grades of dysplasia in both tissue and cytology samples to predict the behaviour of these potentially malignant disorders and to assess the diagnostic utility of cytology samples for ploidy analysis. METHODOLOGY: After obtaining ethical clearance and consent, tissue and cytology samples of leukoplakia were collected and grouped based on the dysplastic findings into low-risk (n=20) and high-risk (n=20). DNA ploidy analysis was done using high resolution flow cytometry and its diagnostic utility was assessed. RESULTS: Diagnostic utility was expressed in terms of sensitivity, specificity, PPV and NPV. On comparing the ploidy status of individual cases between tissue and cytology samples, cytology was able to accurately determine the ploidy status in majority of the cases. In the low-risk group, cytology had a sensitivity and specificity of 100% and a PPV and NPV of 100% with an overall diagnostic accuracy of 100%. Among the high-risk group, cytology had a sensitivity of 80% and specificity of 100% with a PPV of 100% and NPV of 83.33% and had an overall diagnostic accuracy of 90%. Combining both groups together, it had a sensitivity of 85.71% and specificity of 100% with a PPV of 100% and NPV of 92.31% and had an overall diagnostic accuracy of 94.74%. CONCLUSION: Overall, this study showed a positive correlation between cytology and tissue samples and ploidy and grade of dysplasia and cytology proved to be a simple and efficient with a reasonable diagnostic value.