Here, to analyse the functional significance of FAK in HNSCC progression, we disrupted the FAK-mediated signal transduction pathway by expression of the FAK COOH-terminal domain (FAK-related nonkinase, FRNK) or small interfering RNA (siRNA) against FAK in the HNSCC-derived SCC40 and SCC38 cell lines. Here, PTK2 is linked to head and neck squamous cell carcinoma.