STAT3 and head and neck squamous cell carcinoma: We tested p-EGFR (Tyr1068), p-AKT (Ser473), p-ERK(Thr202/204), p-RelA/p65(Ser536), p-STAT3(Tyr703), and each respective phospho-protein’s total protein level by RPPA in two HNSCC cell lines treated with EGF and gefitinib.