FLT3 and acute myeloid leukemia: To investigate the role of HDACis in leukemia maintenance and drug resistance, we generated the FLT3i-resistant AML cells MV-4-11/quizartinib harboring FLT3-ITD and F691L mutations [26], exhibiting a resistance factor (RF) of 5717 for quizartinib (Fig. 5a).