Glutathione S-transferase M1 and T1 status and the risk of laryngeal cancer: a meta-analysis.

BACKGROUND Polymorphic variations in GSTM1 and GSTT1 have been implicated as risk factors for various cancers. A number of studies conducted to assess their association with susceptibility to laryngeal carcinomas have yielded inconsistent and inconclusive results. In the present study, the possible association of laryngeal cancer risk with GSTM1 and GSTT1 null genotypes was explored by a meta analysis. METHOD A meta-analysis was carried out on case-control studies collected from the literature. The pooled odds ratio (OR) and presence of publication bias in those studies were evaluated. RESULTS A total of 20 studies concerning laryngeal cancer were identified. The results showed that the pooled OR was 1.22 (95% CI 1.03 1.43) for the GSTM1 polymorphism while for GSTT1 polymorphism, the pooled OR was 1.23 (95% CI 0.96-1.58). No evidence of publication bias was detected among the included studies. CONCLUSION The results suggest that the GSTM1 deficiency significantly increases susceptibility to laryngeal cancer whereas GSTT1 null genotype might not be a risk factor.