FLT3 and acute myeloid leukemia: While multiple studies (adult and pediatric) have demonstrated the presence of FLT3 mutations in the phenotypic LSC compartment [142,143], it is notable that FLT3 mutations generally are considered a “late” stage modification in the evolution of adult AML [144], and approximately 50% of patients who relapse or progress on FLT3 inhibitor therapy lose their ITD mutations [145].