HPGDS and cancer: The altered drug efflux mechanisms involve an aberrant expression both of P-glycoprotein (P-gp1), belonging to the ABC transporters family that extrudes many types of drugs from cancer cells, and glutathione S-transferases (GSTs), involved in the detoxification pathway, that catalyze the conjugation of glutathione (GSH) to compounds for easy elimination [28,29].