EGFR and non-small cell lung carcinoma: Epidermal growth factor receptor (EGFR), which is encoded by the proto‐oncogene c‐ErbB‐1, is normally expressed in the epidermis at the physiological level and is frequently upregulated or sporadically mutated in various types of solid cancers including non‐small‐cell lung cancer (NSCLC), colorectal, breast, pancreatic, and head and neck squamous cell carcinoma (HNSCC).1, 2, 3