Effect of GSTM1 null genotype on risk of childhood acute leukemia: a meta-analysis

Glutathione S-transferases are important enzymes in the detoxification of a wide range of reactive oxygen species. Recently, there have been a number of studies on the association between Glutathione S-transferase M1 (GSTM1) null genotype and childhood acute leukemia in Chinese, but the results of previous reports are inconsistent. Thus, we performed a meta-analysis to clarify the effect of GSTM1 null genotype on childhood acute leukemia risk. PubMed, Embase, and Wanfang databases were searched to identify case–control studies investigating the association between GSTM1 null genotype and risk of childhood acute leukemia. Between-study heterogeneity was assessed using the I2 statistic method. Odds ratios (OR) with corresponding 95% confidence intervals (95% CI) were pooled to assess the association. Seven case–control studies were finally included in the meta-analysis. There was no between-study heterogeneity among those seven studies (I2 = 0%). Overall, the GSTM1 null genotype was significantly associated with increased risk of childhood acute leukemia in Chinese (fixed effect OR = 2.49; 95% CI, 1.84–3.37; P < 0.001). The cumulative meta-analyses showed a trend of more obvious association between GSTM1 null genotype and risk of childhood acute leukemia in Chinese as data accumulated by year. Sensitivity analysis by omitting single study in turns also did not materially alter the pooled ORs. Therefore, the GSTM1 null genotype is significantly associated with increased risk of childhood acute leukemia in Chinese.