The PPP diverges at the first step of glycolysis, which serves as the largest contributor of cytosolic NADPH and NADPH generation undergoes three irreversible reactions in the PPP oxidative branch.40–42 Studies have proved that NADPH production is dramatically increased by enhancing the flux of glucose into the PPP oxidative branch in various cancers.43,44 Glucose-6-phosphate dehydrogenase (G6PD) that exists as either an active dimer or an inactive monomer dehydrogenates G6P to yield 6-phosphogluconolactone (6-PGL) and NADPH in the first reaction. Here, G6PD is linked to cancer.