IDH1 and cancer: In addition, IDH1/2mt cancer cells have a decreased NADPH production capacity because mtIDH1/2 enzymes have lost the ability to reduce NADP+ to NADPH but instead oxidize NADPH to NADP+ to catalyze the conversion from α-KG to D-2-HG.4,5,10 Together, the D-2-HG accumulation and the decreased NADPH production capacity affect the abovementioned plethora of cellular functions, which may all contribute to oncogenesis and have been extensively reviewed before.2,9,11