Key proteins involved in DNA repair, such as BRCA1, RAD51, and RAD52 in HR, xeroderma pigmentosum group C (XPC) in nucleotide excision repair (NER), and flap endonuclease 1 (FEN1) in base excision repair (BER), influence the susceptibility of various cancers and may be suitable targets in cancer mono- and combination therapy (Ali et al., 2017; Grundy et al., 2020; Hengel et al., 2016; Huang et al., 2016; Li et al., 2021; Lu et al., 2020; Malik et al., 2020; Miki et al., 1994). This evidence concerns the gene FEN1 and cancer.