Mesothelin-related predictive and prognostic factors in malignant mesothelioma: a nested case-control study

Soluble mesothelin-related protein (SMRP) in serum is potentially a sensitive marker of malignant mesothelioma (MM) diagnosis and progression, and may be useful as screening marker. Mesothelin expression in tumors is regarded as a sensitive marker for diagnosis and disease progression, and is a candidate prognostic marker. Levels of SMRP, CA125 and CYFRA 21-1 in pre-diagnostic (1-30 years) serum samples from 47 mesothelioma cases and 141 matched controls were analysed. Mesothelin expression in tumors was assessed. The association between biomarker level and mesothelioma risk and survival was analysed, adjusting for asbestos exposure. Survival related to tumor mesothelin expression, age, sex, histological type, location, asbestos exposure and pre-clinical SMRP was analysed. There was no significant association between biomarker levels and mesothelioma risk when analysed as continuous variables or as tertiles. Biomarker levels <10, 10-19 and >or=20 years before diagnosis were not significantly associated to mesothelioma risk. Mesothelin expressed in >50% of tumor cells was seen in 36 of 47 (77%) tumors. Mesothelin expression in <50% of tumor cells was a significant negative prognostic marker in all cases of malignant mesothelioma (median survival=6 months vs. 12 months, hazard ratio (HR)=2.49, 95%CI 1.17-5.27), and also when only epithelial mesothelioma was analysed (median=6 months vs. 14 months, HR=2.36, 95%CI 1.07-5.22). When adjusted for age and gender, the prognosis was still dismal, but non-significant (HR=1.85, 95%CI 0.85-4.05). High age (>65 years) was an independent negative prognostic factor that was related to both mesothelin expression and asbestos exposure. Mesothelioma of the epithelial type of the peritoneum had a significantly longer survival than epithelial type in pleura and was also related to mesothelin expression.