PRKDC and head and neck squamous cell carcinoma: NHEJ is involved in ~80% of DSB repairs induced by radiation in cancer cells (Kakarougkas and Jeggo, 2014), and DNA-Pkcs inhibitors, such as the oral inhibitor M3814, can potentiate the antitumor activity of IR in HNSCC cell lines in vivo (Zenke et al., 2020).