Recent studies move closer to answering questions about sequential therapy for anaplastic lymphoma kinase-rearranged non-small cell lung cancer

Anaplastic lymphoma kinase (ALK) fusion gene resulting from gene rearrangement was first identified in anaplastic large-cell lymphoma (ALCL) and is characterized by the fusion of nucleophosmin (NPM) and ALK genes (1). Subsequently, this type of fusion gene was described for the first time in lung cancer by Soda et al. through cDNA expression screening of surgically resected specimens from lung adenocarcinoma patients (2). Unlike the fusion gene in ALCL, this gene results from a fusion between echinoderm microtubule-associated protein-like 4 (EML4) and ALK. The two genes are positioned in opposite directions on the short arm of chromosome 2, and the inversion of this region orients the genes in the same direction leading to the formation of the EML4-ALK fusion cancer gene (2).