In addition, the number of CD4+ T helper (Th1) lymphocytes has a significant correlation with CD8+ T cell density in the tumour microenvironment.5 In peripheral blood, T helper 17 (Th17) and T cytotoxic 17 (Tc17) cells were significant predictors of poor prognosis for patients with HNSCC.6 This evidence concerns the gene CD8A and head and neck squamous cell carcinoma.