NPM1 and acute myeloid leukemia: AML patients with NPM1 mutation with absent or low FLT3-ITD AR (<0.5) have similar OS, and are classified as favorable risk by 2017 ELN, whereas AML patients with mutated NPM1 and high FLT3 ITD AR are classified as intermediate-risk along with wild-type NPM1 with absent or low FLT3 ITD AR.