Moreover, given our and other's findings that APE1 acetylation modulates expression of many genes [5, 6, 9, 14, 37], and it enhances its endonuclease activity (present study), it appears that increased APE1 acetylation in tumor cells modulates DNA damage repair, and at the same time also alters gene expression to maintain sustained proliferation. This evidence concerns the gene APEX1 and neoplasm.