ORIGINAL ARTICLE: Endometrial Osteopontin mRNA Expression and Plasma Osteopontin Levels are Increased in Patients with Endometriosis

PROBLEM: The aim of this study was to evaluate osteopontin (OPN) mRNA expression in eutopic endometrium and plasma OPN levels in patients with endometriosis. METHOD OF STUDY: A total of 79 patients with histologically confirmed endometriosis and 43 patients without endometriosis participated in this study. OPN mRNA expression in endometrial tissues was measured by real-time quantitative polymerase chain reaction (PCR) and plasma concentrations of OPN were quantified using a specific commercial sandwich enzyme-linked immunosorbent assays (ELISA). RESULTS: Osteopontin mRNA expression in endometrial tissue was significantly higher in women with endometriosis than in controls (P = 0.010). The mean plasma levels of OPN (mean +/- S.E.M.) in patients with endometriosis and controls were 407.31 +/- 37.80 ng/mL and 165.84 +/- 19.29 ng/mL, respectively (P < 0.001). Receiver operating characteristic (ROC) analysis for plasma OPN revealed an area under the curve (AUC) of 0.894, with a sensitivity of 93.0%, specificity of 72.4%, positive likelihood ratio of 3.37, and negative likelihood ratio of 0.1 using a cut-off value of 167.68 ng/mL. CONCLUSION: Osteopontin may be involved in the pathogenesis of endometriosis and plasma OPN may be a useful non-invasive marker for the diagnosis of endometriosis.