Abstract

Polymorphisms of carcinogen-metabolizing enzymes, known to be involved in metabolism of carcinogens found in tobacco smoke, are relatively common in most populations. Cigarette and bidi smoking has been demonstrated to increase the risk of head and neck cancers in our study group. This study evaluated the risk of head and neck cancers (HNC) in relation to two deletion polymorphisms of the glutathione S-transferase family GST M1 and GST T1. We found that the null GST M1 and GST T1 genotypes were associated with an increased risk of developing head and neck cancers. We found smokers, with null genotypes of GST M1 (68.3%) and GST T1 (57.5%) were at a significantly higher risk of head and neck cancers. It is possible that the decreased activity of GST affects various functions like the mechanisms of DNA damage, including those mediated by tobacco and oxidative stress. The present study investigated whether homozygous gene deletions of GST M1 and GST T1 increases the incidence of head and neck cancers and explored the relationship between the GST genotype patients to clarify the multistep pathogenesis of these cancers based on this possible genetic predisposition. Based on these results it is also concluded that genotyping of GSTs would be a useful biomarker for determining the risk of head and neck cancers in bidi and cigarette smokers.

Key words: Polymorphisms, genotypes, glutathione S-transferases, head and neck cancer.