Impacts of TNF-LTA SNPs/Haplotypes and Lifestyle Factors on Oral Carcinoma in an Indian Population.

BACKGROUND AND OBJECTIVES: To investigate a potential association between single-nucleotide polymorphisms (SNPs) and  haplotypes at the TNFA-LTA locus and the development of oral cancer in an Indian population. MATERIALS AND METHODS: In this study, 150 oral precancer/cancer samples (50 precancer and 100 cancer), along with an equal number of control samples, were genotyped. Six SNPs at the TNF-LTA locus (i.e., -238G/A, -308G/A, -857C/T, -863C/A, -1031T/C, and +252A/G) were analyzed by use of a polymerase chain reaction-restriction fragment length polymorphism method, the assay was validated by sequencing 10 % of samples. RESULTS: The allelic frequencies of TNFA and LTA SNPs were found to be significantly associated with the risk of oral cancer and precancerous lesions in comparison with controls (P < 0.0003). Further haplotypic analysis showed that two haplotypes (ATCTGG and ACACGG) served as risk haplotypes for oral cancer. These haplotypes were also found to be significantly and positively associated with lifestyle habits (tobacco chewing P = 0.04, odds ratio [OR] 3.4) and socioeconomic status (P = 0.01, OR 3.4). We noticed an increased percentage of risk haplotypes correlating with the aggressiveness of oral cancer. The percentages of risk haplotypes were found to be threefold higher in precancer and fourfold higher in advanced stages of oral cancer in comparison with controls. CONCLUSION: Five SNPs at the TNF-LTA locus (i.e., -308G>A, -857C>T, -863C>A, -1031T>C, and +252A>G) were found to be associated with the development of oral cancer. Two haplotypes (ATCTGG and ACACGG) emerged as major risk haplotypes for oral carcinoma progression and were also found to be associated with lifestyle factors and clinical aggressiveness. These findings make the TNF-LTA locus a suitable candidate for a future biomarker, which may be used either for early detection or for helping to improve treatment efficacy and effectiveness.