Prognostic role of osteopontin expression in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) represents highly aggressive neoplasms with a mean survival of approximately 10 months. Osteopontin, a glycoprotein involved in cell-matrix interactions correlated with invasion and metastatic spread in several tumors, has recently been proposed as a serum marker of MPM in asbestos-exposed subjects. The aim of this study was to define the prognostic role of osteopontin in MPM. For the study, 32 long-term survivors (>24 months) and a random sample of 69 short-term survivors (≤24 months) were matched according to the main clinicopathologic features. Immunohistochemical osteopontin expression in tissue specimens was quantified through the HScore (histologic scoring) method and correlated with clinicopathologic parameters and survival. Osteopontin expression was significantly lower in long-term compared with short-term survivors (P < .0001), and overall survival analysis showed that low osteopontin expression was associated with longer survival; multivariate analysis confirmed the value of osteopontin expression as an independent prognostic factor (P < .0001).