EGFR and lung cancer: Non‐small cell lung cancer (NSCLC) represents 80–85% of all lung malignant neoplasm and is one of the primary causes of cancer‐related mortality worldwide.[1, 2] Epidermal growth factor receptor (EGFR) is overexpressed in several tumor types including NSCLC, and the activation of this protein is keenly associated with tumor cell proliferation, invasion, metastasis, angiogenesis, and apoptosis.[3, 4, 5] Erlotinib (ERT), a selective and potent tyrosine kinase inhibitor (TKI), is effective and one of the frontline drugs for NSCLC therapy.