We and others have previously shown that inhibition of poly (ADP) ribose polymerase-1 (PARP1), a member of the SSB base excision repair pathway, is a potent sensitizer of tumor cells to IR (Nowsheen et al., 2011b; Swindall et al., 2013) in HNSCC cells. This evidence concerns the gene PARP1 and head and neck squamous cell carcinoma.