ALK and lung cancer: Translocations involving the anaplastic lymphoma kinase (ALK) represent common oncogenic events in 4%-5% of patients with non–small cell lung cancer (NSCLC).1 Echinoderm microtubule-associated protein-like 4 (EML4) acts as a translocation partner and is involved most frequently in ALK translocations leading to increased activity of the ALK tyrosine kinase.2 Activating ALK translocations promote proliferation and tumor growth.