ALK and lung cancer: The brain is a common site of metastasis in patients with lung cancer, with incidence rates reaching up to 50%.1–5 Despite advances in therapies targeting epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK), as well as improvements in immunotherapy and radiotherapy, the prognosis for patients with brain metastases (BM) remains dismal.6–10 Elucidating the molecular mechanisms underlying BM formation is therefore essential for identifying diagnostic markers and developing effective therapeutic strategies.