To evaluate the radiosensitivity of HNSCC cells varying in p53 status, an isogenic pair of HNSCC cell lines, derived from the same patient differing only in their p53 status, HN30 (wild-type TP53, wtp53) and HN31 (TP53 mutations, C176F and A161S) were used along with their p53 knockdown counterparts (HN30 shp53 and HN31 shp53). This evidence concerns the gene TP53 and head and neck squamous cell carcinoma.