TGFB1 and head and neck squamous cell carcinoma: IL-33 could support the expansion of ST2+Foxp3+ Treg cells (127), increasing the secretion of inhibitory cytokines IL-10 and TGF-β1 in ST2+Foxp3+ Treg cells and promoting their suppressive function in head and neck squamous cell carcinoma (HNSCC).