IL17A and head and neck squamous cell carcinoma: In the present study, HNSCC tumor-infiltrating lymphocytes (TILs), which secrete typical cytokines associated with Th1-, Th2-, Th9-, Th17-, and Th21-polarized inflammation (including IFN-γ, IL-4, IL-9, IL-17, and IL-21), were identified using flow cytometric analysis.