Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase, initially discovered in anaplastic large cell lymphoma, but chromosomal rearrangements resulting in a fusion gene, most commonly with echinoderm microtubule-associated protein-like 4 (EML4), occur in 3-7% of NSCLC (51, 52). The gene discussed is EML4; the disease is anaplastic large cell lymphoma.