Mutations in the NPM1gene are one of the most frequent driver mutations in AML and commonly indicate a better risk prognosis. NPM1encodes the nuclear chaperone protein, NPM, that plays a role in protein formation, ribosome biogenesis, DNA replication, and the cell cycle. Mutations in NPM1are nearly exclusively in exon 12 and often co-occur with epigenetic modifier mutations, like IDH1and IDH2.