ALK and lung cancer: ALK gene rearrangements result in various ALK fusion oncogenes including EML4 (echinoderm microtubule-associated protein like 4)–ALK3 in lung cancers, TPM3 (tropomyosin 3)-ALK in ALCL4 and TPM3/4–ALK5 in inflammatory myofibroblastic tumours (IMT).6