The impact of vascular endothelial growth factor single nucleotide polymorphisms in the development and severity of endometriosis: a systematic review of the literature.

Abstract Objective To review the impact of single nucleotide polymorphisms (SNPs) of the vascular endothelial growth factor (VEGF) gene in the development and severity of endometriosis. Search strategy We searched Medline, Scopus, Clinicaltrials.gov, EMBASE, Cochrane Central Register of Controlled Trials CENTRAL and Google Scholar databases for published studies in the field. Selection criteria We included prospective and retrospective observational studies. Data collection and analysis Data extraction was performed using a modified data form that was based in Cochrane`s data collection form for intervention reviews. Main results Twenty studies were included that investigated the frequency of the various alleles of the -460C/T, +405 G/C, +936C/T, -2578A/C and -1154 G/A SNPs. The Hardy-Weinberg equilibrium revealed that the different genotypes were comparable among patients with endometriosis and control women, as well as among patients with mild and severe forms of the disease. No differences were observed in the expression of the various alleles in the majority of cases. Ethnical variations were observed; however, the results should be regarded as inconclusive due to the small amount of available data. Conclusions The results of our meta-analysis suggest that the investigated single nucleotide polymorphisms are unlikely to significantly contribute to the development and severity of endometriosis.