ABSTRACT:
Tobacco is an established risk factor for oral cancer. Polymorphism of a great number of phase I and phase II XME genes have been widely elucidated over the last three decades, may play a role in determining an individual’s susceptibility to oral cancer in particular and in combination with specific environmental exposure such as smoking. Glutathione S-transferases (GSTM1 and GSTT1) involved in detoxify tobacco smoke constituents and polymorphisms within GSTM1 and GSTT1 genes can result in a complete lack of enzyme activity. In this hospital based case-control study, 104 oral cancer patients (cases) and 104 controls were studied to determine the risk of the disease due to polymorphisms at GSTM1 and GSTT1 loci. Overall, we observed no statistically significant associations between the polymorphisms and oral cancer genotypes on GSTT1 locus, but the simultaneous presence of two mutant genotypes, one of each of two loci (GSTM1 and GSTT1) increased about four fold risk of oral cancer (OR= 3.79, 95% CI- 0.32-3.54). In conclusion, our preliminary results are consistent with earlier published study supporting associations between oral cancer and GSTM1 and GSTT1 homozygous null genotypes.