Our observation here is consistent with two prior studies showing that APE1 is important for the ATR DDR pathway activation in response to oxidative DNA damage in human cancer cells MDA-MB-231 and PANC1 cells, and ultraviolet damage in non-dividing nucleotide excision repair-deficient (i.e. XPC-/-) cells (Li et al., 2022; Vrouwe et al., 2011). Here, ATR is linked to cancer.