ALK and lung cancer: The discovery of the transforming echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) fusion gene in lung cancer in 2007 revealed that ALK is not only a driver gene for very rare types of hematological cancer but can also serve as a therapeutic target for non-small cell lung cancers (NSCLC) [1-4].