Circulating MicroRNAs Identified in a Genome-Wide Serum MicroRNA Expression Analysis as Noninvasive Biomarkers for Endometriosis

Context: There is currently no reliable noninvasive biomarker for the clinical diagnosis of endometriosis. Previous analyses have reported that circulating microRNAs (miRNAs) can serve as biomarkers for a number of diseases. Objective: The study aims to detect the serum miRNAs that are differentially expressed between endometriosis patients and negative controls to evaluate the potential of these miRNAs as diagnostic markers for endometriosis. Design: A total of 765 serum miRNAs were profiled using a TaqMan microRNA array in a pool of 10 endometriosis patients and a pool of 10 negative controls, and a set of selected miRNAs were further analyzed in a validation cohort consisting of sera from 60 patients and 25 controls including 10 samples used in array profiling. Results: The relative expression levels of miR-199a and miR-122 were found to be up-regulated in endometriosis patient samples compared with control samples, whereas miR-145*, miR-141*, miR-542-3p, and miR-9* were down-regulated in endometriosis patients. Importantly, the relative expression of miR-199a (P < 0.05) and miR-122 can be used to discriminate between severe and mild endometriosis. We also found that miR-199a is well correlated with pelvic adhesion and lesion distribution (P < 0.05) and associated with hormone-mediated signaling pathways. Furthermore, we investigated the diagnostic value of these molecules and confirmed the optimal combination of miR-199a, miR-122, miR-145*, and miR-542-3p with area under the curve of 0.994 (95% confidence interval = 0.984–1.000, P < 0.001) and a cutoff point (0.4950) of 93.22% sensitivity and 96.00% specificity. Conclusions: Our study demonstrated that the circulating miRNAs miR-199a, miR-122, miR-145*, and miR-542-3p could potentially serve as noninvasive biomarkers for endometriosis. miR-199a may also play an important role in the progression of the disease. This is the first report that circulating miRNAs serve as biomarkers of endometriosis.