HoxA9 overexpression frequently occurs in association with rearrangements of the Mixed Lineage Leukemia locus at 11q23 (MLL) [5,6], but is also associated with trisomy 8 AML [7] and the t(7;11)(p15;p15) translocation which fuses NUP98 to HoxA9 [8]. This evidence concerns the gene HOXA9 and acute myeloid leukemia.