miRNA Expression Profiles in Ovarian Endometriosis and Two Types of Ovarian Cancer-Endometriosis-Associated Ovarian Cancer and High-Grade Ovarian Cancer.

Endometriosis-associated ovarian cancer (EOC) consisting of endometrioid cancer and clear-cell ovarian cancer could be promoted by many factors. miRNAs, which are small, non-coding molecules of RNA, are among them. The aim of this study was to detect miRNAs connected with the malignant transformation of endometriosis. FFPE (formalin-fixed, paraffin-embedded) samples of 135 patients operated on for endometriosis and different types of ovarian cancer (EOC and HGSOC-high-grade serous ovarian cancer) were studied. Healthy ovarian tissue was used as a control group. From the expression panel of 754 miRNAs, 7 were chosen for further tests according to their ROC (receiver operating characteristic) curves: miR-1-3p, miR-125b-1-3p, miR-31-3p, miR-200b-3p, miR-502-5p, miR-503-5p and miR-548d-5p. Furthermore, other potentially important clinical data were analysed, which included age, BMI, Ca-125 concentration, miscarriages and deliveries and concomitant diseases such as hypertension, type 2 diabetes and smoking. Among the miRNAs, miR200b-3p had the lowest expression in neoplastic tissues. miR31-3p had the highest expression in women without any lesions in the ovaries. miR-502-5p and miR-548-5p did not differ between the studied groups. The examined miRNA panel generally distinguished significantly normal ovarian tissue and endometriosis, normal ovarian tissue and cancer, and endometriosis and cancer. The malignant transformation of endometriosis is dependent on different factors. miRNA changes are among them. The studied miRNA panel described well the differences between endometriosis and EOC but had no potential to differentiate types of ovarian cancer according to their origin. Therefore, examination of a broader miRNA panel is needed and might prove itself advantageous in clinical practice.

miR 31-3p Has the Highest Expression in Cesarean Scar Endometriosis.

Micro-RNAs expression can vary between different forms of endometriosis, but data on miRNA expression in cesarean scar endometriosis is lacking. The present study is comprised of 30 patients with endometriosis in the cesarean scar (scar endometriosis, SE), 14 patients with deep infiltrating endometriosis (DIE), 47 patients with endometrioma (ovarian endometrial cyst, OE), and 33 patients with healthy ovarian tissue as the control group (CG). In the initial experiment to identify possible dysregulated miRNAs, the levels of 754 miRNAs in formalin-fixed paraffin-embedded tissue (FFPE) samples from OE, high-grade ovarian cancer, endometrioid ovarian cancer, and CG were measured. We identified seven potentially dysregulated miRNAs: miR-1-3p, miR-31-3p, miR-125b-1-3p, miR-200b-3p, miR-548d, miR-502, and miR-503. We then examined the expression profiles of each of these miRNAs individually in the SE, DIE, OE, and CG FFPE samples using RT-qPCR. miR-31-3p had significantly higher levels of expression and miR-125b-1-3p had significantly lower levels of expression in SE compared to the controls. Overall, the higher expression levels of miR-31-3p and the lower expression levels of miR-125b-1-3p are consistent with the benign nature of SE. Importantly, the results of the present study demonstrate the possibility of using miRNA to monitor the risk of malignant transformation of endometriosis tissue.