ALK and lung cancer: Rearrangements in the anaplastic lymphoma kinase (ALK) gene occur in 3–7% of patients with non-small cell lung cancer (NSCLC) (Shaw et al. 2009), and ALK-positive lung cancer has been defined as a distinct clinical and molecular subtype of NSCLC (Lin et al. 2017; Shaw et al. 2009; Soda et al. 2007).