CHEK1 and head and neck squamous cell carcinoma: In addition, the combination of niraparib with the Chk1 inhibitor MK-8776 has been shown to enhance the radiosensitivity of HPV(+) HNSCC cells, whereas co-administration with the Wee1 inhibitor MK-1775 seems to further enhance the radiosensitivity of HPV(−) HNSCC cells in vitro [211].