KIT and leukemia: As is shown in the survival plot, except for the c-Kit−Gr-1low fraction (Fr 3), cells in the other three subpopulations were all able to induce leukemia with the onset of c-Kit+Gr-1high fraction (Fr 2) being the fastest (median survival of 31.5 days) and c-Kit+Gr-1low fraction (Fr 1) being the slowest (median survival of 49 days) (Fig. 4b).