The primary aim of this non-interventional study, Registry for the Epidemiological and Scientific evaluation of EGFR mutation status in patients with newly diagnosed locally advanced or metastatic NSCLC (REASON), was to generate data on EGFR mutation status from a large cohort of predominantly Caucasian patients and to correlate it with clinicopathological characteristics. Here, EGFR is linked to non-small cell lung carcinoma.