Current biomarkers such as EGFR, ALK, ROS1 and PD-L1 have led to improvements in the clinical management of NSCLC patients but there is still a need to better understand the mechanisms underlying efficacy of therapeutic agents and to investigate novel biomarkers to improve clinical management, response outcomes and cost-effectiveness of drugs in advanced NSCLC patients. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.