Promising data has been reported demonstrating that the radiosensitivity of HNSCC, particularlyrelatively radioresistant HPV-negative HNSCC, can be increased by inhibitors targeting proteins involved in DNA damage repair (PARP, ATR, and DNA-Pkcs) and in DNA damage checkpoint activation (CHK1). This evidence concerns the gene PARP1 and head and neck squamous cell carcinoma.