EML4 and non-small cell lung carcinoma: ALK rearrangements, primarily involving EML4-ALK fusions but also including KIF5B-ALK, TFG-ALK, and KLC1-ALK among others, are detected in approximately 3–5% of NSCLC cases.46 These cases share clinical features with EGFR mutations, such as adenocarcinoma histology and a history of mild or no smoking.47 Fusion transcripts containing the ALK kinase domain may promote kinase activation in downstream survival signaling, thereby providing vulnerability to TKI treatment.48