Soluble Mesothelin-Related Peptide Level Elevation in Mesothelioma Serum and Pleural Effusions. Soluble mesothelin-related peptide (SMRP) is a potential marker for malignant pleural mesothelioma

Harvey I. Pass, MD, Anil Wali, PhD, Naimei Tang, PhD, Alla Ivanova, PhD, Sergey Ivanov, PhD, Michael Harbut, MD, Michele Carbone, MD, PhD, and Jeffrey Allard, PhD
Department of Cardiothoracic Surgery, Division of Thoracic Surgery, New York University School of Medicine, New York, New York; Karmanos Cancer Institute, Detroit, Michigan; Cancer Research Center of Hawaii, Honolulu, Hawaii; and Fujirebio Diagnostics Inc, Malvern, Pennsylvania

Background. Soluble mesothelin-related peptide (SMRP) is a potential marker for malignant pleural mesothelioma (MPM), which may be useful for screening high-risk asbestos-exposed individuals. Methods. We evaluated SMRP in serum from MPM patients (n 90), lung cancer patients (n 170), age and tobacco-matched asbestos-exposed individuals (n 66), and in MPM pleural effusions (n 45), benign effusions (n 30), and non-MPM effusions (n 20) using the MesoMark enzyme-linked immunosorbent assay kit (Fujirebio Diagnostics, Malvern, PA). Receiver operating characteristic (ROC) curves were used to define true and false positive rates at various cutoffs. Results. Mean serum SMRP levels were higher in MPM compared with lung cancer (5.67 0.82 nM [mean standard error of the mean vs 1.99 0.43 nM, p < 0.001), and stage I MPM SMRP levels (n 12; 2.09 0.41 nM) were significantly higher than those in asbestos-exposed

individuals (0.99 0.09 nM, p 0.02, respectively). Stage 2 to 4 SMRP serum levels were significantly higher than those for stage 1 MPM. The area under the ROC curve for serum SMRP was 0.81 for differentiating MPM and asbestos-exposed individuals; cutoff 1.9 nM (sensitivity 60%, specificity 89%). The MPM pleural effusion SMRP was significantly higher than benign or other non-MPM pleural effusions (65.57 11.