ERCC2 and head and neck squamous cell carcinoma: Seven SNPs of the NER genes involved in the HNSCC are listed as follows: XPC Ala499Val, XPC Lys939Gln, XPD Asp312Asn, XPD Lys751Gln, XPG His1104Asp, ERCC1 C8092A, and XPA G23A.