EGFR and head and neck squamous cell carcinoma: The upregulation and activation of EGFR in response to MAPK pathway inhibition have been described in several cancer types and are known to limit the effect of MEK inhibitors [39, 40, 41, 42], but to date and to the best of our knowledge, upregulation of EGFR in response to inhibition of the MAPK pathway has not been studied in HNSCC.