Molecular markers in lung cancer

PURPOSE OF REVIEW: As demonstrated by the recent therapeutic advances in nonsmall cell lung cancer (NSCLC), a personalized approach can considerably reduce its mortality. RECENT FINDINGS: Molecular tests identifying genetic mutations in NSCLC have led to a shift towards more effective and personalized therapies targeted to these alterations. Adequate tissue is required for diagnosing, subcharacterizing, and genotyping NSCLC by morphological, immunohistochemical, and molecular techniques. Endobronchial ultrasound (EBUS)- or transesophageal ultrasound (EUS)-guided needle aspiration and radial-probe EBUS-guided methods have proved to be reliable in diagnosis and/or staging of the disease. Small specimens obtained by these methods are sufficient for molecular analysis if a rational and multidisciplinary approach to specimen acquisition and processing is exercised. Coordination between the bronchoscopist and cytopathologist in managing specimens is critical for optimal use of obtained tissue. If available, rapid on-site evaluation can be beneficial in assessing quality and quantity of the specimen, and allocating for cell block, immunohistochemistry, and molecular studies. SUMMARY: The rationale for histologic and molecular testing of lung cancer specimens should be well understood by bronchoscopists so that specimens obtained by EBUS- or EUS-guided methods are managed in an optimal fashion that will provide cytologic specimens sufficient to guide targeted therapy.