Development of immunotherapy for brain metastasis (Review).

Brain metastasis (BM) is associated with a poor prognosis, with the typical overall survival rate ranging from weeks to months in the absence of treatment. Although the concept of immune privilege in the central nervous system has eroded over time, the advent of immunotherapy has opened a new set of potential therapeutic options for patients with BM. Recently, immunotherapy has been demonstrated to confer survival advantages to patients with multiple malignancies commonly associated with BMs. Data from a number of clinical trials have demonstrated that immune checkpoint inhibitors are effective for patients with BM. In addition, cellular therapies, including the application of chimeric antigen receptors T‑cell therapy and dendritic cell vaccine, have also been utilized in the treatment of BM. In the present review, preclinical and clinical evidence supporting the applicability of immunotherapy for the treatment of BMs from melanoma, non‑small cell lung cancer (NSCLC) and renal cell carcinoma (RCC) were examined, where the challenges and safety of this treatment modality were also discussed.