EGFR and non-small cell lung carcinoma: The clinical activity of EGFR targeting agent, tyrosine kinase inhibitor (TKI) such as gefitinib and erlotinib, is closely associated with EGFR mutation status in NSCLC, and the clinical relevance of EGFR mutations as a positive predictive factor for EGFR TKI therapy has been well documented [1]–[5].