Serum Biomarker for Diagnosis of Endometriosis

Endometriosis is estimated to affect 10% of women during the reproductive years. The lack of a non‐invasive diagnostic test significantly contributes to the long delay between onset of the symptoms and definitive diagnosis of endometriosis. This case–control study was conducted to identify specific endometriosis antigens using 2D gel analysis in women with endometriosis (n = 5) and without endometriosis (n = 5). Differentially expresses spots were analyzed using matrix‐assisted laser desorption/ionization‐time‐of‐flight/mass spectrometry (nanoLC‐ESI‐MS/MS) with MASCOT analysis, in order to identify the corresponding proteins. ELISAs were performed on a different cohort of endometriosis (n = 120) and healthy patients (n = 20) in order to confirm the differential expression of the identified proteins. ROC analysis of ELISA results confirmed the statistical significance of the differential expression for one of these proteins: Zn‐alpha2‐glycoprotein (P = 0.019). We propose the analysis of the expression level of this protein in the serum as a new non‐invasive diagnostic test for endometriosis. J. Cell. Physiol. 229: 1731–1735, 2014. © 2014 Wiley Periodicals, Inc.