HOXA9 and acute myeloid leukemia: This suggests that SETDB1 is responsible for the increase in H3K9me3 at these promoters in cells overexpressing SETDB1 and that SETDB1 may be responsible for depositing a basal level of H3K9me3 at the Meis1 and Hoxa9 promoter genes in resting state MLL-AF9 AML cells.