How and when to use genetic markers for nonsmall cell lung cancer

PURPOSE OF REVIEW: Many driver mutations that determine the malignant behavior of lung cancer have been identified in recent years. The promise of therapies targeted to the specific molecular pathways altered by such mutations has made genetic testing in nonsmall cell lung cancer (NSCLC) attractive to clinicians. We reviewed recent research on clinically relevant genetic and molecular tests for patients with NSCLC, with an emphasis on the tests linked to actionable mutations that influence therapy and improve outcomes. RECENT FINDINGS: Mutations in the epidermal growth factor receptor gene (EGFR) and translocations involving the anaplastic lymphoma kinase (ALK) gene have been shown to be common driver mutations in lung adenocarcinoma. The presence or absence of these mutations has been demonstrated to predict response to targeted therapy in many recent studies. Targeted therapies for patients with mutations in the EGFR domain or the echinoderm microtubule-associated protein-like 4 anaplastic lymphoma kinase translocation have been shown to be effective and are approved for use. Ongoing studies continue to define the extent of their utility and may continue to expand their indications. Sufficient tissue for genetic analysis can be obtained from cytologic samples, including those obtained from endobronchial ultrasound-guided transbronchial needle aspiration. SUMMARY: Genetic testing for driver mutations is useful in identifying patients with NSCLC who are likely to respond to targeted therapy. These tests are best used in patients with adenocarcinoma who have advanced-stage cancer.