Trial goal: Determine whether DNA mismatch repair (MMR) loss and microsatellite instability (MSI) predict benefit from a dendritic cell (DC) tumor vaccine in glioma/GBM. Interventions: • DC vaccine (biological, autologous cell-based immunotherapy) given with surgery in one cohort. Mechanism: Patient-derived dendritic cells are loaded with tumor antigens to enhance antigen presentation (MHC I/II), activating CD8+ cytotoxic and CD4+ helper T cells to kill glioma cells. Targets/cells/pathways: • Antigen-presenting dendritic cells and effector T lymphocytes (CD8+, CD4+). • Tumor cells with MMR deficiency/MSI-high status (MLH1, MSH2, MSH6, PMS2), associated with higher neoantigen load. • Antigen presentation and T-cell activation pathways, tumor immune microenvironment. The study also develops imaging (radiomics/deep learning) markers of MMR/MSI to noninvasively predict vaccine benefit.