APEX1 and acute myeloid leukemia: The obtained results clearly demonstrated that: (i) the proteolytic events in AML cells involve the removal of the protein N-terminus, as we previously demonstrated in other cells [13], and specifically cleavage at Lys31 and Lys32; (ii) proteolysis is not ascribable to a granzyme-like activity, contrarily to previous investigations [11,12]; (iii) the cleavage of the APE1 N-terminal domain in AML cells depends on the proteasome complex activity; (iv) possibly, acetylation can modulate this process.