IDH1 and neoplasm: Instead, mutant IDH displays a neomorphic activity converting αKG into D-2-hydroxyglutarate (D-2HG), although reducing NADPH.9 As a result, mutant IDH may alter the redox state of cells, modulate the activity of metabolic and epigenetic tumor suppressor enzymes that use αKG as a co-substrate.10 Loss of IDH function may also alter normal mitochondrial function and promote a metabolic switch in cancer cells to glycolysis.11, 12