TNFRSF4 and head and neck squamous cell carcinoma: Lastly, we assessed the specific gene expression in the Treg subpopulation and found that TNFRSF4 (Tumor Necrosis Factor Receptor Superfamily Member 4) is differentially expressed in core Tregs and is correlated with significantly better survival, raising the possibility that this gene could play a key role in the mechanisms underlying Tregs in HNSCC.