OBJECTIVETo study the association of genetic polymorphism of glutathione S-transferase (GSTM1 and GSTT1) with susceptibility to primary liver cancer in Chinese.

METHODSLiterature search of the PubMed, Chinese National Knowledge Infrastructure, and ISI Web of Science databases identified 25 relevant case-control studies of glutathione S-transferase genetic polymorphisms and primary liver cancer, representing a total of 2788 cases and 5548 controls. The extracted data was applied to the RevMan v4.2 software for meta-analysis. Data with significant heterogeneity was assessed by the fixed effects model, otherwise a random effects model was applied. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.

RESULTSThe correlation between the GSTM1 and GSTT1 null genotypes and susceptibility to primary liver cancer showed statistical significance (cases: P = 1.8 * 10(-11) and controls: P = 4.6 * 10(-11); Pearson's Chi-squared test). The OR value for GSTM1 was 1.67 (95% CI: 1.39-2.01) and for GSTT1 was 1.59 (95% CI: 1.26-1.96). In the GSTM1-GSTT1 interaction analysis, both GSTM1 and GSTT1 were null genotypes with OR = 3.34 (95% CI: 2.23-5.00), which was higher than the null genotype for either one of them alone and which indicated higher relative susceptibility. Compared with individuals for whom both GSTM1 and GSTT1 were non-null genotypes, the presence of at least one null genotype showed higher risk of primary liver cancer.

CONCLUSIONThe null genotypes of glutathione S-transferase genetic polymorphisms GSTM1 and GSTT1 are risk factors for primary liver cancer respectively, and their associated risk is increased when both are present.