Combined Serum Mesothelin and Plasma Osteopontin Measurements in Malignant Pleural Mesothelioma

Introduction: Malignant pleural mesothelioma (MPM) is a lethal tumor related to asbestos exposure. At present, the only instruments for screening and diagnosis are based on radiological tests, posing evident economic and radio-protectionist problems. Some authors are evaluating biological indicators, such as plasma osteopontin (pOPN) and serum soluble mesothelin-related peptides (SMRP). This study aimed to evaluate whether a combination of these two markers could increase sensitivity and specificity in diagnosis of epithelioid MPM. Methods: We enrolled 93 healthy subjects, 111 individuals with benign respiratory disease (BRD), and 31 patients with MPM, histologically and/or cytologically confirmed. SMRP and pOPN levels were determined using commercially available enzyme-linked immunosorbent assay kits. Though a logistic regression analysis, SMRP and pOPN were combined and translated into a new index, called "combined risk index." Results: Differences in both SMRP and pOPN mean values between epithelial MPM patients and healthy subjects or BRD patients were statistically significant (p < 0.0001), whereas there was no difference in SMRP and pOPN mean values between healthy subjects and BRD patients. The performance in MPM diagnosis resulted improved by the combination of the two markers. The results of our study should be confirmed by a larger scale and, possibly, a multi-center study, which could better take into consideration the influence of some possible confounding factors such as glomerular filtration rate and other blood parameters. Conclusions: We combined SMRP and pOPN dosages to increase diagnostic accuracy. This study showed for the first time that combined SMRP and pOPN measurements can increase both sensitivity and specificity in terms of combined risk index.