Accelerated leukemia development and increased LICs by KIT^D816V/Y. (A) Disease latency in secondarily transplanted mice with leukemic cells of Cbfb^+/56m; Tg(Mx1-Cre) (black diamonds) and Cbfb^+/56m; Tg(Mx1-Cre)/KIT^D816V/Y (gray squares). Each recipient mouse was given 10⁶ leukemia cells. (B) Leukemia incidences from limiting dilution transplantation with Cbfb^+/56m; Tg(Mx1-Cre)/KIT^D816Y leukemia cells (N = 4; black lines) and Cbfb^+/56m; Tg(Mx1-Cre) leukemia cells (N = 2; gray lines). Numbers of cells injected per mouse are shown on x-axis. N = 5 in each dose group. (C) Genomic Southern blot hybridization for clonality analysis. Each lane is from one secondarily transplanted mouse. Panels A, B, and C are 3 different donors (lanes not labeled had degraded DNA). (D) Leukemia cell viability in culture after PKC412 treatment. Gray line indicates Cbfb^+/56m; Tg(Mx1-Cre)/KIT^D816Y mice (N = 4); and black line, Cbfb^+/56m; Tg(Mx1-Cre) mice (N = 5; *P < .01).