EGFR and head and neck squamous cell carcinoma: Recently, early clinical trial data in head and neck squamous cell carcinoma (HNSCC) revealed the presence of an EGFR-AS1(c.2361G>A) synonymous mutation4, high baseline phospho-MAPK (ref. 5) and MAPK1p.E322K mutation6 as additional potential biomarkers for erlotinib sensitivity.