Recent studies showed that TGF-β2 and TGF-β1 can induce CXCR4 expression in several types of tumor cells including HNSCC cells [34-37] and leukocytes [38-40], via TGF-β type I receptor-dependent non-Smad signaling pathways. This evidence concerns the gene TGFB1 and head and neck squamous cell carcinoma.