GSTP1 c.341C>T gene polymorphism increases the risk of oral squamous cell carcinoma

Glutathione S Transferases (GST) are anti-oxidant enzymes involved in detoxification of cellular and exogenous carcinogens and oxidative products of reactive oxygen species. Genetic polymorphisms can attenuate the detoxification capacity of GST and consequently increase the susceptibility to carcinogenesis. There are eight classes of GST enzymes of which pi subtype is the predominant form expressed in the oral mucosa. c.341C > T single nucleotide polymorphism (rs1138272) in GSTP1 gene, is a functional variation that reduces the enzymatic activity of GST pi. We carried out a 1:2 case-control study involving 270 individuals to determine the association of c.341C > T variation with the risk of oral squamous cell carcinoma. GSTP1 c.341C > T variation was genotyped by PCR-RFLP method. GST pi expression in the tumour sample was determined by immunohistochemistry. Tobacco consumption was the major risk factor among cancer patients. The odds ratio for the risk of oral squamous cell carcinoma in individuals with the minor allele was 4.5 (0.95 CI = 2.3-8.9; P = 0.000004). The genotype was found to follow dominant mode of inheritance (OR 4.4 [0.95 CI = 2.1-9.2]; P = 0.00006). Our results support the conclusion that c.341C > T variation in GSTP1 increases the risk of OSCC in patients habituated to tobacco consumption.