Association of glutathione S-transferase M1 and T1 null polymorphisms with the development of cervical lesions: a meta-analysis

Abstract

Objectives: An accumulation of evidence suggests that gene-based self-susceptibility may contribute to the development of cancer. Some studies have found that particular polymorphisms of the glutathione S-transferase M1 and T1 genes are associated with increased risk of cervical lesions, but other studies have had contrary results. The present meta-analysis evaluated the association of glutathione S-transferase M1 and T1 null polymorphisms with the development of cervical lesions. In addition, stratified analyses were performed in an attempt to identify any race-specific effects.

Study design: Twenty-one related studies were included in the meta-analysis, comprising glutathione S-transferase M1 data from 1423 patients with cervical lesions and 2415 healthy matched controls, and glutathione S-transferase T1 data from 2081 patients with cervical lesions and 2287 healthy matched controls. The fixed-effect model (Mantel-Haenszel method) and the random-effect (DerSimonian and Laird) model were used to examine the difference in frequency of glutathione S-transferase M1 and T1 null polymorphisms between pre- and invasive cervical lesions. Subgroup analyses were also conducted to evaluate any race-specific effect on the frequencies of glutathione S-transferase polymorphisms in cervical lesions. Odds ratios (OR) and 95% confidence intervals (CI) were calculated. Heterogeneity was assessed using the heterogeneity metric (I²) and Chi-squared test.

Results: The glutathione S-transferase M1 null polymorphism was associated with increased risk of low-grade intra-epithelial lesions (OR 1.37, 95% CI 1.05-1.77), but no increased risk of high-grade intra-epithelial lesions (OR 1.29, 95% CI 0.87-1.8) or invasive cervical cancer (OR 1.20, 95% CI 0.99-1.46). The association seemed to be confined to Southeast Asians (OR 1.97, 95% CI 1.44-2.71). No significant associations were found for the glutathione S-transferase T1 null polymorphism for any of the populations.

Conclusions: The glutathione S-transferase M1 null polymorphism significantly increases susceptibility to early-stage cervical lesions in Southeast Asians. However, the glutathione S-transferase T1 null polymorphism does not appear to be a risk factor for cervical lesions in any population.