The Massachusetts General Hospital (MGH) research team reported a remarkable treatment response in a patient participating in a clinical trial of a novel immune-system-based cancer therapy. Treatment with an investigational CAR T-cell therapy induced complete remission of a brain metastasis of the difficult-to-treat tumor diffuse large-B-cell lymphoma (DLBCL), which had become resistant to chemotherapy – the first report of a response to CAR T-cells in a central nervous system lymphoma.