G6PD and neoplasm: Trans-dehydroandrosterone (DHEA), a non-competitive antagonist of the PPP key enzyme glucose-6-phosphate dehydrogenase (G6PDH), reduces NADPH levels, resulting in a lack of substrate to maintain the reduction status of glutathione (GSH), which reduces the resistance of tumor cells to oxidative stress [13] and increases the tumor cell sensitivity to chemotherapeutic drugs.