Evaluation of soluble mesothelin-related peptide as a marker additional to cytology for diagnosing malignant pleural mesothelioma effusions

e17533 Background: Detection of soluble mesothelin-related peptide (SMRP) levels in serum has been proposed to help the diagnosis of malignant pleural mesothelioma (MPM). In this study we evaluated the SMRP levels in pleural effusions of MPM (MPM-PE), the clinical importance and usefulness of SMRP detection in MPM-PE and whether it can have an additional value to cytological analysis (Cyt). Methods: We studied 52 MPM-PE, 129 benign PE (B-PE) and 94 non-MPM pleural metastasis PE (Mts-PE). In all PE samples, both cytology and SMRP detection were performed. SMRP levels were estimated by means of the MesoMark ELISA kit (Fujirebio Diagnostic, Malvern, PA). Diagnostic performance parameters were estimated through the ROC analysis, Youden's index was applied to obtain the best cut-off level and the degree of correlation was estimated by Diagnostic Odds Ratio (DOR) and by P-value (P) with Chi-square test. Results: The median SMRP levels were significantly higher in MPM-PE (28.2 nM) than in B-PE (3.2 nM) or Mts-PE (3.8 nM). MPM-PE vs B-PE yielded an AUC of 84.5 (P