MEIS1 and acute myeloid leukemia: This indicates that although the first oncogenic event (MLL-fusion protein or overexpression of Hoxa9/Meis1) can induce the transformation of cells, thus generating pre-leukemic stem cells, dysregulated Wnt signaling is needed for the development and/or propagation towards full-blown leukemic stem cells (LSCs) in these mouse models of AML.