ALK and non-small cell lung carcinoma: Approximately 2–7% NSCLC patients harbor anaplastic lymphoma kinase (ALK) gene rearrangements (3, 4), leading to aberrant expression and oncogenic activation of ALK. Echinoderm microtubule-associated protein-like 4 (EML4)-ALK is the canonical and most common ALK gene arrangement found in NSCLC, by which multiple EML4 breakpoints fuse in frame with the kinase domain of ALK (5).