To confirm the presence of CTCF at these loci in primary AML cells, we performed CTCF ChIP-seq on primary AML patients with the NPM1c insertion mutation in NPM1, t(9;11) and t(11;19) MLL rearrangements, and t(8;21) creating the RUNX1-RUNX1T1 gene fusion, which displayed the expected HOXA and HOXB, HOXA only, and no HOX expression patterns, respectively (Table S1 and Fig. S1A). Here, KMT2A is linked to acute myeloid leukemia.