EGFR and head and neck squamous cell carcinoma: We reported that HNSCC cells harboring an endogenous MAPK1E322K mutation (HSC-6) or HNSCC cells hemizygous for wild type MAPK1 (FaDu) transfected with mutant MAPK1E322K demonstrated enhanced EGFR phosphorylation and activation of downstream signaling [6, 7, 12].