As an important player in DNA damage repair system, FEN1 is a well‐known enzyme in the BER and AEE pathways, and it is also an important component in other DNA repair pathways, such as nonhomologous end joining and homologous recombination.29, 30, 31 When cancer cells are treated with DNA damage‐related drugs, FEN1 is supposed to be recruited to the damage foci and rescues the damaged DNA in specific sequential order. Here, FEN1 is linked to cancer.