KLF4 and acute myeloid leukemia: In flow-sorted murine BM KIT+Gr1+ AML cells, expression levels of transcription factor genes such as Irf8, Irf5, and Klf4 (which promote monocytic lineage differentiation) were significantly lower in Hoxa9/FOXC1 AMLs in comparison with Hoxa9/IRX3 and Hoxa9/MTV AMLs (Figure 6A).