FLT3 and acute myeloid leukemia: Although a multi-targeted kinase inhibitor, midostaurin, has shown a significant effect in combination with the standard chemotherapy against FLT3-mutated AML and was recently approved by the US Food and Drug Administration (FDA) for its treatment [6, 7], clinical trials with specific FLT3 tyrosine kinase inhibitors alone have so far given only limited successes [3], at least partly because of emergences of resistance mutations after sustained FLT3-ITD inhibition in the case of FLT3-specific inhibitor AC-220 (quizartinib) [8].