PRKDC and head and neck squamous cell carcinoma: This would correlate with studies in HPV-negative HNSCC cells describing downregulation of DNA-Pkcs using siRNA in UTSCC15 and UTSCC45 cells [25], as well as the DNA-Pkcs inhibitors KU0060648 in HN4 and HN5 cells [17], and IC87361 in UTSCC54, UTSCC74B and UTSCC76B cells [18], which were shown to enhance radiosensitisation.