Mass General Brigham Dec 4 2025 Researchers at Mass General Brigham have modified a herpes simplex virus (HSV-1) that stimulates the immune system to attack glioblastoma cells. A single dose of the modified virus increased T-cell, natural killer cell, and myeloid cell responses in the tumor microenvironment and increased the overall survival in preclinical models. Results are published in Nature Cancer . Glioblastoma is among the most aggressive and treatment-resistant brain tumors. Previous