IDH1 and neoplasm: Tumor-derived IDH1 and IDH2 mutations not only simultaneously lose their normal catalytic activity: the production of α-ketoglutarate (α-KG) from the convertion of isocitrate, but also gain a neomorphic enzymatic activity: the reduction of α-KG to D-2-hydroxyglutarate (D-2-HG) (Dang et al., 2009; Yan et al., 2009; Zhao et al., 2009).