CCR4 and head and neck squamous cell carcinoma: Specifically, the results showed STAT1 of T-helper 1 (Th1) cells, STAT6 of T-helper 2 (Th2) cells, BCL6 of follicular helper T (Tfh) cells, STAT3 of T-helper 17 (Th17) cells, FOXP3, CCR8, CD25 (IL-2R α) and STAT5B of Tregs, IRF4 of T-helper 9 (Th9) cells, FOXO4, CD196 (CCR6) and CD194 (CCR4) of T-helper 22 (Th22) cells are significantly correlated with YTHDC2 expression in HNSCC (Correlation > 0.35, P < 0.0001; Fig. 6).