Expanding experimental evidence indicates that MDSC-derived TGF-β, calprotectin (S100A8/A9), and VEGF promote PMN formation and metastasis by communicating with the immune system, endothelial cells, fibroblasts, and hepatic stellate cells [83], although the exact mechanism in HNSCC remains to be confirmed. This evidence concerns the gene TGFB1 and head and neck squamous cell carcinoma.