ALK and lung cancer: Lung cancer causes the most cancer-related death worldwide;19 it can be divided into small cell lung cancer and non-small cell lung cancer (NSCLC), which takes 85% of all cases.20 Comprehensive cancer genome sequencing found both genetic and epigenetic alterations in NSCLCs.21–23 Alterations in key genes, such as Ras, ALK and EGFR, have previously been shown to drive lung tumorigenesis.24–27 Although targeted therapy has been developed and utilized widely to treat EGRF and ALK mutant lung cancer, many other lung cancers remain poorly characterized.