Preoperative radiation therapy targeting brain metastases can activate immune pathways that typically are suppressed, results of a retrospective, observational study showed.Ionizing radiation enhanced T-cell receptor diversity and upregulated antigen presentation within the brain metastases microenvironment.Patients with enriched T-cell receptor diversity, as well as greater presence and density of tumor-infiltrating lymphocytes (TILs), exhibited favorable prognoses. The enhanced cellular immunity could make tumors more receptive to immunotherapy, according to investigators.“It certainly is