Glutathione S-transferase P1 Ile105Val polymorphism and oral cancer risk: a meta-analysis.

Objective The glutathione S-transferase P1 (GSTP1) gene has been suggested to play an important role in the pathogenesis of oral cancer. However, the results have been inconsistent. In this study, we performed a meta-analysis to clarify the association of GSTP1 Ile105Val polymorphisms with oral cancer risk. Methods Published literature from PubMed and EMBASE were retrieved. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using fixed- or random-effects model. Results 13 studies (1803 oral cancer cases and 2998 controls) for GSTP1 Ile105Val polymorphism were included in the meta-analysis. The results indicated that there was no significant association between GSTP1 Ile105Val polymorphism and oral cancer in the overall population (OR=1.30, 95%CI=0.92-1.38, I(2)=48.0%, p for heterogeneity=0.027). Further subgroup analysis by ethnicity suggested that GSTP1 Ile105Val polymorphism was significantly associated with oral cancer only in East Asians (OR=1.64, 95%CI=1.16-2.31, I(2)=0.0%, p for heterogeneity=0.525), but not in Caucasians (OR=1.16, 95%CI=0.73-1.82, I(2)=7.5%, p for heterogeneity=0.299), Africans (OR=1.10, 95%CI=0.37-3.28), South Asians (OR=1.20, 95%CI=0.69-2.08, I(2)=74.3%, p for heterogeneity=0.021) and mixed population (OR=0.91, 95%CI=0.70-1.20, I(2)=39.7%, p for heterogeneity=0.174). Conclusions The present meta-analysis has limited evidence to support the association of GSTP1 Ile105Val polymorphism with HCC risk in the overall population. However, GSTP1 Ile105Val polymorphism might be associated with risk of oral cancer in East Asians.