CTCF and acute myeloid leukemia: These included E1 and E3 (accessible in 12 of 36 and 13 of 36 primary AML cases, respectively), which became strongly acetylated in drug-resistant K562 cells, and the CTCF binding site C1 (accessible in 32 of 36 primary AML cases) (Figure 3A and Figure 6, C and D).