Loss of PU.1 from the nucleus in NPM1c AML switches the function of nuclear transcription factors CCAAT/enhancer binding protein alpha (C/EBPα) and Runt-related transcription factor 1 (RUNX1) from activation to suppression of more than 500 terminal differentiation genes (Gu et al., 2018). This evidence concerns the gene RUNX1 and acute myeloid leukemia.