EGFR mutation in lung cancer: tumor heterogeneity and the impact of chemotherapy

EGFR inhibitors have been examined as treatments for unselected NSCLC patients until the discovery that activating EGFR mutations render the tumors highly sensitive to these drugs (1,2). Since then, several studies have demonstrated that the presence of an EGFR activating mutation identifies a different population of NSCLC patients, with a significantly better prognosis, provided EGFR inhibitors are one of the treatment lines. Thus, testing for such mutations is recommended as part of the initial workup of advanced NSCLC patients.