IDH1 and neoplasm: Multivariate analysis on IDH1-R132H expression, differentiation, tumor stage, and CEA level revealed that IDH1-R132H expression (HR, 0.156, P<0.001), differentiation (HR, 2.653, P=0.013), and tumor stage (HR, 1.551, P=0.022) are independent prognostic risk factors (Table 5).