Identification of Serum Biomarkers for Diagnosis of Endometriosis Using Multiplex Immunoassays

Endometriosis is a common gynecologic disorder characterized by chronic pelvic pain, dysmenorrhea, and infertility. Although this condition places significant financial burden on the healthcare system and negatively affects patient's quality of life, the pathophysiology of the disease remains unclear, and noninvasive diagnostic methods are insufficient. The object of this study was to identify potential biomarkers for endometriosis from peripheral blood. We hypothesized that serum biomarkers modified in endometriosis patients would be detected by multiplex cytokine panel, and identification of a combination of these biomarkers would improve diagnostic power. A total of 141 women, aged 15-52 years with regular menstruation, participated in this study. Twenty-one serum cytokines were detected using the commercially available MILLIPLEX MAP Human Cytokine/Chemokine Kit Panel IV. Among these cytokines, breast- and kidney-expressed chemokine (BRAK)/chemokine (C-X-C motif) ligand 14 (CXCL14) was significantly decreased, and proliferation-inducing ligand (APRIL)/tumor necrosis factor ligand superfamily member 13 (TNFSF13) was significantly increased in endometriosis group. APRIL/TNFSF13 and BRAK/CXCL14 alone or in combination, however, failed to show adequate sensitivity or specificity for the diagnosis of endometriosis. Combination of APRIL/TNFSF13 and BRAK/CXCL14 with serum CA-125 levels yielded significantly higher sensitivity (71.2%) for detecting endometriosis without compromising specificity (80.8%) than CA-125 alone in a logistic regression model (P = 0.050). In conclusion, we identified a biomarker combination that detects endometriosis better than CA125 alone. Therefore, we conclude that multiplex cytokine panel is an efficient method for detecting endometriosis, and analysis of additional cytokine panels may lead to identification of a novel biomarker combination with superior diagnostic power.