Null Glutathione S-transferase T1 and M1 Genotypes and Oral Cancer Susceptibility in China and India - a Meta-analysis

Objective: Genetic variation is considered to strongly impact on detoxification of carcinogens and therefore is related to cancer risk. However, findings for the null genotypes of GSTT1 and GSTM1 have not always been consistent. Therefore the present meta-analysis was conducted. Methods: We accessed the reported study at different research areas and used various databases, including PubMed and Wanfang Med Onlion from 1990 to May 1st 2013. We calculated the odds ratio (OR), 95% confidence interval (CI) and P value for oral cancer by using Review Manager 5.1 and STATE 12. Results: We found that there was no increased oral cancer risk among subjects carrying GSTM1 and GSTT1 null genotype (OR=1.35, 95%CI=0.68-2.68, P=0.39) and (OR=1.41, 95%CI=0.72-2.77, P=0.31) in the Chinese population. In contrast, in studies in India a significant correlation between GSTM1 null genotype and oral cancer was observed (OR=1.59, 95%CI=1.20-2.11, P=0.001), but not in GSTT1 (OR=1.21, 95% CI = 0.84-1.74, P=0.31). Conclusion: We discovered that GSTM1 deletion polymorphism had a significant effect on the susceptibility of oral cancer in the Indian population.