Association between matrix metalloproteinase-2 and matrix metalloproteinase-9 polymorphisms and endometriosis: A systematic review and meta-analysis.

Matrix metalloproteinase-2 ()-735C/T and -1562C/T polymorphisms have been indicated in the predisposition to endometriosis. However, due to the small sample sizes of previous studies, the results remain inconclusive. The present meta-analysis was conducted to detect the association between the two genetic polymorphisms and the risk of endometriosis by pooling all the available data. Electronic databases, including PubMed, Embase, Web of Science and CNKI, were searched comprehensively for studies examining a link between and polymorphisms and endometriosis. The strength of the association was assessed based on the pooled odds ratio with a 95% confidence interval, which was calculated using either the fixed- or random-effect model. Following the inclusion criteria, 6 case-control studies were included. The total number of participants was 2,486 (558 cases and 797 controls concerning the -1562C/T polymorphism, and 525 cases and 606 controls concerning the -735C/T polymorphism). No significant association was identified between the -735C/T or -1562C/T polymorphism and endometriosis. In further stratified analysis, no significant association was identified between the -1562C/T polymorphism and endometriosis. The present meta-analysis revealed no association between the -735C/T and -1562C/T polymorphisms and the risk of developing endometriosis. Considering the limitations of the meta-analysis, well-designed studies with larger sample sizes are required.