Anaplastic lymphoma kinase (ALK) is a member of the insulin receptor protein–tyrosine kinase (RTK) superfamily, and has been recognized as an efficacious therapeutic target for the treatment of non-small cell lung cancer (NSCLC) because of its effect on the EML4-ALK fusion protein that occurs in patients with NSCLC1,2. This evidence concerns the gene EML4 and non-small cell lung carcinoma.