NPM1 and acute myeloid leukemia: This identified a region of active chromatin in the center of the HOXA cluster that overlapped CBSA6/7 and CBSA7/9, and was conserved in the MLL-rearranged and NPM1-mutant AML samples, and normal CD34+ cells (which also express HOXA and HOXB genes) (Figs. 2a and S2A).