Decoding the immune microenvironment: precision immunotherapy for medulloblastoma subtypes

Medulloblastoma is a severe pediatric brain tumor with distinct molecular subtypes-WNT, SHH, Group 3, and Group 4-each having unique genetic drivers and immune microenvironments. This review highlights the immune characteristics of each subtype: SHH is rich in tumor-associated macrophages (TAMs), whose role in tumorigenesis is debated; Group 3 features cytotoxic T cells often neutralized by immune checkpoints like PD-L1, causing T cell exhaustion; and Group 4 is marked by natural killer (NK) cells and B cells. These immune landscapes, including tumor-associated astrocytes (TAAs) and abnormal vascular networks, influence tumor growth, spread, and treatment response. Precision immunotherapy must be tailored to specific subtypes. This article discusses CAR T-cell therapy targeting antigens like B7-H3 and GD2, prevalent in SHH subtypes, and examines immune checkpoint blockades targeting PD-1/PD-L1 and CD47-SIRPα. It also highlights innovative methods like oncolytic viruses to transform "cold" tumor microenvironments and combination therapies using CSF1R inhibitors and tumor-associated antigens to boost anti-tumor responses. Understanding the immune microenvironment's subtype-specific heterogeneity in medulloblastoma is crucial for advancing precision immunotherapy and improving patient outcomes.