PARP1 and head and neck squamous cell carcinoma: This increased susceptibility correlated with reduced nuclear EGFR, attenuation of NHEJ, and persistence of DNA damage following IR (Nowsheen et al., 2011).Similarly, a study by Güster et al., in 2014 revealed that inhibiting PARP could enhance the responsiveness of HPV-positive HNSCC cells to radiation therapy, and similar outcomes were detected in laboratory settings.