OBJECTIVE: Special attention has been paid to genetic mechanisms that might have a significant impact on the context of the risk of developing endometriosis, in recent years. The study aimed to analyze the expression levels of three inflammatory biomarkers Interleukin-6 (IL-6), vascular endothelial growth factor, and matrix metalloproteinases-9, in the increased incidence of endometriosis. METHODS: The material for genetic testing was tissue slices embedded in paraffin blocks from these patients with endometriosis (I-II) ( RESULTS: The expression levels of IL-6 and vascular endothelial growth factor gene in the peripheral blood and peritoneal fluid of these endometriosis patients were not statistically significant lower than in the control group. Besides, the significant differences were found in IL-6, vascular endothelial growth factor and matrix metalloproteinases-9 between eutopic endometrial tissues of the endometriosis group, compared to the control group
and these increased significantly with the severity of the disease. In addition, there was significant difference in the expression level of matrix metalloproteinases-9 in peripheral blood and peritoneal fluid, and the difference was statistically significant in these patients with stages III-IV, compared with these patients with stages I-II. Among them, the Revised American Society for Reproductive Medicine classification of endometriosis was used in the group of patients with endometriosis. CONCLUSION: These patients with endometriosis showed the significant differences in matrix metalloproteinases-9 expression in peripheral blood, peritoneal fluid, and eutopic and ectopic endometrial tissues as the condition worsens. The research suggested that the determination of matrix metalloproteinases-9 in peripheral blood has certain value in evaluating the condition of endometriosis, which might play an important role in the pathogenesis of endometriosis and be explored for postoperative recurrence monitoring.