The multivariate analysis showed CD9 expression is an independent predictor of survival of mesothelioma patients with an HR of 1.99 (P=0.0261) as well as older age (HR, 2.10), IMIG stage III/IV (HR, 2.04), sarcomatoid histology (HR, 6.65), patients treated with chemotherapy alone (HR, 0.37) and patients treated with extrapleural pneumonectomy (HR, 0.26) (Table IV). The gene discussed is CD9; the disease is mesothelioma.