Mass General Brigham Oct 8 2025 A multi-institutional study from the Accelerating GBM Therapies Through Serial Biopsies TeamLab, led by investigators from the Mass General Brigham Cancer Institute, found that serially testing tumor samples can help detect when a cancer treatment is activating the immune system in recurrent glioblastoma (GBM), even when traditional imaging measures cannot. Their results are published in Science Translational Medicine .   GBM is the most aggressive type of brain