title: Null genotypes of GSTM1 and GSTT1 and endometriosis risk: a meta-analysis of 25 case-control studies.
abstract: Endometriosis is one of the most frequent benign gynecological disorders. Numerous studies have shown an association between GSTM1 and/or GSTT1 polymorphisms and endometriosis susceptibility. However, these associations remain inconclusive. To derive a more precise estimation, we conducted a comprehensive search to identify all existing studies and then performed a meta-analysis. Electronic literature searches of the PubMed, Chinese Biomedical, and China National Knowledge Infrastructure databases were performed up to December 2013. GSTM1-, GSTT1-, and dual-null genotypes were analyzed independently, and pooled odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated by comparing the null genotype with other genotypes using the random-effects or fixed-effects model. Twenty-five and 16 independent studies on GSTM1 and GSTT1 polymorphisms, respectively, and five GSTM1-GSTT1 interaction analyses were identified and included in this meta-analysis. Both GSTM1- and GSTT1-null genotypes increased risk of endometriosis (OR = 1.54, 95% CI: 1.30-1.83, P<0.001; OR = 1.41, 95% CI: 1.10-1.82, P = 0.007; respectively). Moreover, we found a significant positive association between the dual null genotype GSTM1-GSTT1 and endometriosis susceptibility (OR = 1.33, 95% CI: 1.03-1.72, P = 0.027). This meta-analysis provides evidence that null genotypes of GSTM1 and/or GSTT1 contribute to risk of endometriosis. Further investigations are required to confirm these findings.
authors.affiliation: Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China; Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.
authors.forename: Haili
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Department of Urology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Jiming
authors.initials: J
authors.lastname: Bao
authors.affiliation: Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China; Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.
authors.forename: Shuguang
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Epidemiology, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, China; Department of Pathology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Shen
mesh_terms: D016022:Case-Control Studies; D004715:Endometriosis / Q000201:enzymology* / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans
chemical_list: D005982:Glutathione Transferase; C413545:glutathione S-transferase T1