XRCC1 and head and neck squamous cell carcinoma: In HNSCC cells, utilising FaDu and UMSCC6 (originating from the hypopharynx and oropharynx, respectively), we confirmed again the effectiveness of the same siRNA sequences in supressing protein levels of OGG1, PARG, Pol β and XRCC1 (Figs. 3A and 4A, respectively).