TGFB1 and head and neck squamous cell carcinoma: One paradox associated with the link between p‐EMT, metastasis, and TGF‐β signaling is the observation that components of the TGF‐β signaling pathway are frequently mutated in SCC, including HNSCC, and some tumor keratinocytes are unresponsive to TGF‐β ligand [17, 18].