Furthermore, the fact that derivative A2780 and 2008 cisplatin-resistant cancer cell lines exhibit normal NER capacity to remove Pt-GG, indicates that low level of certain NER proteins (e.g., XPC and XPG in CP70 cell line, XPC, XPF, and ERCC1 in CDDP cell line, XPF in 2008C13 cell line) may not result in the low NER capacity. This evidence concerns the gene ERCC4 and cancer.