CTCF and acute myeloid leukemia: Further analysis of the interactions between SKAP2 intron 1 and the HOXA cluster in the primary AML samples demonstrated that reads supporting this loop were most abundant near the CTCF binding site CBSA7/9 in the NPM1c sample, compared with the HOXA1 gene in the sample with RUNX1-RUNX1T1 (Fig. 6d).