NPM1 and acute myeloid leukemia: While addition of ATRA to intensive chemotherapy resulted in better overall survival in the NPM1 mutated subgroup (Schlenk et al., 2009, 2016), large studies by others could not confirm beneficial effects of ATRA in AML patients (Estey et al., 1999; Milligan et al., 2006; Burnett et al., 2010), which may be due to the timing of ATRA dosing and/or different patient populations.