6-mercaptopurine (6-MP) contributes substantially to remarkable improvement in the survival of childhood acute lymphoblastic leukemia (ALL) patients. However, 6-MP also has dose-limiting toxicities, particularly life-threatening myelosuppression, due to genetic polymorphisms in enzymes that metabolize 6-MP. | Optimal predictor for 6-mercaptopurine intolerance in Chinese children with acute lymphoblastic leukemia NUDT15 TPMT or ITPA genetic variants