HOXA9 and myeloid leukemia: As Meis-Pbx-Hox orthologs in C. elegans have been shown to participate in cell fate determination in association with asymmetric cell division [37], the important role of Meis1 in asymmetric/symmetric division of cells in the HSC compartment is also highlighted by data showing that NUP98-HOXA9, an oncogenic partner of Meis1 in human myeloid leukemia [16], [38], promotes symmetric self-renewal of hematopoietic precursors [39].