PvuII and XbaI in Estrogen Receptor 1 (ESR1) Polymorphisms and Susceptibility to Endometriosis Risk

BACKGROUND: Studies have shown that variants in PvuII and XbaI loci are associated with the occurrence and progression of endometriosis (EM), while the results were in great debate. METHODS: A systematic review and meta-analysis were conducted to evaluate the role of PvuII and XbaI polymor-phisms in estrogen receptors (ESR1). The primary sources of the reviewed studies through December 2018, with restriction on the language of English and Chinese, were Pubmed and Embase and CNKI. The pooled odds ratio 95% confidence intervals (CIs) were calculated to evaluate the associations of Pvull and Xbal polymorphisms with the risk of EM by using the STATA 14.0 software. RESULTS: A total of 18 studies with 4,975 patients, 2,222 in the case group, 2,753 in the control group, were in the final analysis. Overall pooled outcomes did not indicate significant correlations between the ESR1 Pvull/Xbal polymorphisms and the EM development. In subgroup analysis, PvuII was associated with endometriosis only for stage I - III and only under a recessive model (OR = 1.61, 95% CI: 1.03 to 2.07; p = 0.03). Xbal was associated with endometriosis only for the non-PCR-RFLP genotype method and also only under a recessive model (OR = 2.10, 95% CI: 1.21 to 4.47; p = 0.04). CONCLUSIONS: This present meta-analysis reported that polymorphisms of PvuII or Xbal were not related to the susceptibility to EM except for a slight association of stage I-III endometriosis and non-PCR-RFLP under recessive model. Future, well-designed large studies are eagerly awaited to confirm our conclusions.