Multivariate analysis using the Cox proportional hazards model of mesothelioma patients showed loss of CD9 expression as an independent predictor of overall survival in patients with malignant mesothelioma with an HR 1.99 (P=0.0261) in addition to age, IMIG staging, histology and therapeutic regimen (Table IV). Here, CD9 is linked to malignant mesothelioma.