Excision repair cross-complementary 1 (ERCC1) is a key protein involved in the process of NER and ERCC1-xeroderma pigmentosum (ERCC1-XPF) catalyzes incision on the incision 50 side to the site of DNA damage (Parker et al., 1991; Bessho, 1995). Here, ERCC1 is linked to xeroderma pigmentosum.