NUDT15 and acute lymphoblastic leukemia: Similarly, NUDT15, an enzyme involved in detoxification of 6-MP metabolites, showed a strong association with 6-MP intolerance in the maintenance phase of ALL therapy (Moriyama et al., 2016), and it has hence been recently integrated in the updated CPIC guidelines for thiopurine dosing (Relling et al., 2019).