A study discovered the existence of a fusion gene in 3%-7% of nonsmall- cell lung cancer (NSCLC), almost entirely in adenocarcinoma patients. The novel fusion comprising portions of the echinoderm microtubule-associated-protein-like 4 (EML4) gene and the anaplastic lymphoma kinase (ALK) gene resulted from a small inversion within chromosome 2p, and appears to be mutually exclusive of EGFR and KRAS mutations1, 2.