{"paper_id":"9c2ced29-0975-4904-b88c-12d67b605717","body_text":"Abstract\nEndometriosis, defined as the growth of endometrial-like tissue outside the uterus, leads to the emergence of chronic inflammatory reactions, which are influenced by the plasminogen activator systems that are known to play a role in fibrinolysis. Hypofibrinolysis due to the excessive expression of the plasminogen activator inhibitor-1 (PAI-1) gene occurs in endometriotic cells. It has been known that the PAI-1 level is lower in normal endometrial cells than in endometriotic cells. The aim of this study is to assess the methylation level of PAI-1 in association with ovarian and peritoneal endometriosis tissues. This was a comparative cross-sectional study conducted on 13 women with ovarian endometriosis, 5 with peritoneal endometriosis, and 8 without endometriosis. DNA from the patient samples was isolated and subjected to bisulfite conversion. DNA methylation was observed by performing the methylation-specific polymerase chain reaction (MSP) method, followed by electrophoresis. The methylation level of PAI-1 was determined by measuring the band intensity using the ImageJ software. The results were statistically analyzed using the Kruskal–Wallis test. A twotailed p value of <0.05 was considered to be statistically significant. Statistically significant difference was noted in the methylation levels of PAI-1 in ovarian endometriosis and peritoneal endometriosis samples compared with those noted in control samples (p = 0.006 and p = 0.003, respectively). The methylation levels in both sample types were lower than those in the control samples. However, the difference between the methylation levels of PAI-1 in peritoneal endometriosis and ovarian endometriosis were not statistically significant (p > 0.05). We found a low methylation level in the promoter region of PAI-1 gene, which led to an increase in the gene expression that may contribute as a risk factor in ovarian endometriosis and peritoneum endometriosis.\nContent from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.","source_license":"CC0","license_restricted":false}