HOXA9 and leukemia: Once mice developed full-fledged AML, this was further confirmed by analysis of blood smear and BM cytospin morphology: Hoxa9/IRX3 recipients developed leukemias exhibiting significantly greater differentiation block in comparison with Hoxa9/MTV controls, as demonstrated by the proportion of blast cells being on average twice as high in the former versus the latter and the proportion of more differentiated leukemia cells being approximately half as much (Figures 3G and 3H).