The echinoderm microtubule-associated protein-like 4 (<i>EML4</i>)-anaplastic lymphoma kinase (<i>ALK</i>) fusion gene, a driver mutation in lung carcinoma, is fairly common in lung adenocarcinoma but rare in large cell neuroendocrine carcinoma (LCNEC). The gene discussed is EML4; the disease is lung adenocarcinoma.