Therefore, we investigated the frequency and phenotypes of wt sequence p53 peptide-specific CTL in patients with HNSCC (n = 33) by flow cytometric analysis using HLA-A*0201 tetrameric peptides (tet) complexed with the wt sequence p53264–272 or p53149–157 peptide and co-staining with phenotypic markers. The gene discussed is TP53; the disease is head and neck squamous cell carcinoma.