EML4 and non-small cell lung carcinoma: Anaplastic lymphoma kinase (ALK) fusions are detected in many cancers with the highest detection rate in NSCLC.[2] ALK fusion is an important driver gene in NSCLC, fusion partners of which have been discovered gradually, including EML4, CMTR1, KLC1, TNIP2 and CUX1.[3–7] However, ALK double fusion in NSCLC is still rare even though ALK fusion is detected in about 4% of lung adenocarcinoma.