More generally, these studies with TF-1 cells suggest that Flt3-ITD is the primary inhibitor target for A-419259 in Flt3-ITD+ AML, although the presence of Hck and Fgr may modulate Flt3-ITD inhibitor sensitivity especially in the presence of Flt3-ITD kinase domain mutations. The gene discussed is FGR; the disease is acute myeloid leukemia.