Based on these findings, several phase III trials are comparing first-line treatment of advanced NSCLC with chemotherapy or EGFR TKI in specific populations of patients: (a) in a clinically-enriched subgroup; or (b) in a biomarker-selected subgroup - those with documented EGFR exon 19 or 21 mutations. This evidence concerns the gene EGFR and non-small cell lung carcinoma.