The univariate analysis demonstrated that high frequencies of IL-17-expressing cells (including Th17, Tc17, and IL-17+ cells), tumor (T) factors, lymph node metastasis (N), and TNM staging were significantly associated with poor overall survival in HNC, though all covariates did not reach statistical significance in the subsequent multivariate analysis (Supplementary Table 3). This evidence concerns the gene IL17A and metastatic malignant neoplasm in the lymph nodes.