EGFR and head and neck squamous cell carcinoma: Overexpression of EGFR (epidermal growth factor receptor), a transmembrane protein belonging to the EGFR tyrosine kinase family, occurs in 90% of HNSCC; further, cetuximab, which binds to the extracellular region of EGFR, is the only targeted therapy approved for the treatment of HNSCC [9].