MLLT3 and acute myeloid leukemia: Upon disease development, however, Smyd2−/− and Smyd2+/+ HSPCs gave rise to undistinguishable AML phenotypes, as judged by either leukemic blast counts in peripheral blood (Figure 3B), spleen size (Figure 4A) or the Gr-1+CD3− immunophenotype of MLL-AF9-positive tumor cells (tracked by the associated Venus fluorescent marker), confirming their myeloid identity (Figure 4B).