TGFB1 and head and neck squamous cell carcinoma: In turn, the overexpression of TGF-β1 observed in HNSCC promotes angiogenesis and endothelial proliferation [142] because it is known that TGF-β1 activates Smad3 phosphorylation and regulates TNC, CDKN1A, and CDKN2A expression in order to promote proliferation of endothelium progenitor cells [144].