G6PD and cancer: Recent research has revealed several mechanisms by which cancer cells regulate NADPH production: (1) the activation of AKT phosphorylates NAD kinase (NADK), leading to increased activity; (2) the promotion, by mutant p53, of the enhanced synthesis of NADPH from NADP by upregulating glucose-6-phosphate dehydrogenase (G6PD); and (3) the interaction between calmodulin and NADK, which enhances NADPH production.