FLT3 and myeloproliferative neoplasm: As activating FMS-like tyrosine kinase 3 (FLT3) mutations are common (~30%) in myeloid malignancies with normal karyotype and are found in ~10% cases with -7/del(7q) lesions26,27,40,41, we generated Cux1+/fl;Flt3ITD/+;Vav-iCre+ (herein referred to as Cux1+/−;Flt3ITD) mice to model Cux1 haploinsufficiency in the context of a heterozygous, activating Flt3ITD mutation—which alone leads to chronic myeloproliferative disease but not AML in knock-in mice40,42.