NPM1 and acute promyelocytic leukemia: The molecular feature of somatic mutations in newly diagnosed and relapsed APL is defined by frequent alterations of FLT3, NRAS, KRAS, and ARID1A/B genes, and the lack of mutations in non-M3 AML genes (e.g. DNMT3A, NPM1, IDH1/2, and ASXL1) (10).