IRX3 and acute myeloid leukemia: Consistent with the cell-cycle status of in vitro transformed Hoxa9/IRX3 cells, analysis of blood at 4, 8, and 12 weeks post-transplantation demonstrated reduced donor:recipient chimerism in blood in Hoxa9/IRX3 versus Hoxa9/MTV recipients (Figure 3D), and Hoxa9/IRX3 recipient mice exhibited delayed onset of donor-derived AML in comparison with Hoxa9/MTV recipients (median 125 versus 270 days) (Figure 3E).