ALK and adenocarcinoma: ALK gene fusions are primarily found in adenocarcinoma subtypes of non-small cell lung cancer (NSCLC), mainly co-occurring with mutations in other genes, such as TP53 and BIM. ALK alterations are more frequently identified in younger, non-smoking patients with advanced lung adenocarcinoma, and are associated with a higher propensity for brain metastases (4, 5).