Single nucleotide polymorphism in hMLH1 promoter and risk of tobacco-related oral carcinoma in high-risk Asian Indians

hMLH1 is a member of mismatch repair genes (MMR) that plays a crucial role in correcting replication errors, cell cycle arrest, apoptosis and oxidative stress. We explored the risk associated with hMLH1 − 93 A>G (rs 1800734) single nucleotide polymorphism (SNP) with the oral squamous cell carcinoma (OSCC) in Asian Indians. We genotyped 242 patients with tobacco-related OSCC and 205 healthy controls by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. The frequency of AA genotype was found to be significantly (Pc < 0.0006) lower in patients as compared to the controls (21.49% vs. 47.8%) while GG genotype showed significantly higher (Pc < 0.0006) prevalence in patients as compared to the healthy controls (41.32% vs. 13.66%). In logistic regression analysis AG (adjusted OR = 1.95, 95% CI = 0.72-5.26) and GG genotype (adjusted OR = 4.5, 95% CI = 1.54-13.16, P = 0.006) appeared susceptible when compared with the wild-type AA genotype. The allelic distribution showed that variant G allele is significantly higher (Pc < 0.0004) in patients and associated with increased risk (adjusted OR = 2.36, 95% CI = 1.33-4.19, P = 0.003) as compared to the wild-type A allele. Altogether, our results suggest that the hMLH1 − 93 A>G polymorphism is associated with the higher risk of tobacco-related OSCC in Asian Indians and could be useful in screening population at a higher risk.