NPM1 and leukemia: Specifically, in participants of AAML0531, high relative expression of MEF2C was associated with a lower prevalence of cytogenetically/molecularly defined low-risk disease and higher prevalence of standard-risk disease, largely because of a lower prevalence of CBF leukemias or mutations in NPM1 or CEBPA and a higher prevalence of leukemias with monosomy 7 or abnormalities involving 11q23.