MEIS1 and acute myeloid leukemia: Although the stimulatory effect of HOXA6 on bone marrow cell proliferation has been previously documented [21,22], this is the first report of AML induction in mice by HOXA6 in co-operation with MEIS1. The second group includes the mouse with MEIS1 and HOXB6 (Fig 5B, Mouse #2–10).