Although the underlying molecular mechanism remains to be determined, recent genetic screens identified APE2 as a synthetic lethal target in BRCA1- or BRCA2-deficient human colon cancer cell line DLD-1, human ovarian cancer cell line PEO1, or engineered human epithelial cell line RPE1-hTERT under unperturbed conditions (Mengwasser et al., 2019; Alvarez-Quilon et al., 2020). Here, BRCA2 is linked to ovarian cancer.