15 genes were present in both subsets and included in the HNSCC DNA repair gene candidate list (XRCC1, MLH3, PMS1, RAD51B, XRCC3, RAD54B, BRCA1, SHFM1, GEN1, FANCE, FAAP20, SPRTN, SETMAR, HUS1, and PER1). This evidence concerns the gene PER1 and head and neck squamous cell carcinoma.