Immunotherapy Approaches for Pediatric Brain Tumors

Immunotherapy for childhood brain tumours is evolving rapidly, driven by the need to overcome limitations of conventional treatments and the unique biology of paediatric central nervous system malignancies. These tumours often harbour low mutational burdens and reside behind the blood–brain barrier, creating an immunologically “cold” environment. Key strategies include tumour-specific vaccination to elicit mutation-targeted T-cell responses, immune checkpoint blockade to reinvigorate exhausted lymphocytes, adoptive cell therapies such as chimeric antigen receptor T (CAR-T) cells or γδ T cells, and modulation of the tumour microenvironment (TME) to enhance immune infiltration. Advances in methylation-based profiling and liquid biopsy have refined patient stratification, identifying “hot” immune phenotypes most likely to benefit from treatment. Early-phase trials of peptide vaccines against neoantigens such as H3K27M, coupled with adjuvants like poly-ICLC, have shown safety and immunogenicity. Concurrently, exploration of innate immune effectors—tumour-associated macrophages and γδ T cells—reveals both pro- and anti-tumoural roles that may be harnessed therapeutically. Integration of these approaches promises personalised regimens that balance efficacy with minimised neurotoxicity in the developing brain.

Research from Nature Portfolio

Pan-tumour immune profiling across over 6,000 predominantly paediatric central nervous system tumours has delineated three distinct immune clusters linked to molecular subtype, prognosis and expression of immunotherapeutic biomarkers such as cytolytic scores and PD-L1. This framework enables identification of medulloblastoma, rhabdoid tumour and high-grade glioma subsets with “hot” microenvironments suitable for checkpoint blockade or vaccine strategies. A first-in-human study of a long-peptide vaccine targeting the H3K27M mutation in diffuse midline glioma demonstrated safety and mutation-specific CD4+ T-cell responses across diverse HLA types, with signs of clinical benefit in select patients. Foundational work in Sonic Hedgehog medulloblastoma revealed that tumour-associated macrophages can exert anti-tumour activity, challenging the prevailing view of macrophages as uniformly immunosuppressive and suggesting that therapies aiming to reprogram or augment these cells may improve outcomes.

Immunotherapy Approaches for Pediatric Brain Tumors publication trend

The graph below shows the total number of articles in immunotherapy approaches for pediatric brain tumors across all publications each year (not limited to Nature Index journals).

Technical terms

Blood–brain barrier: A selective vascular interface that limits entry of cells and molecules into the central nervous system.

Chimeric Antigen Receptor T (CAR-T) cells: Genetically engineered T lymphocytes that express receptors specific for tumour antigens, enabling targeted cytotoxicity.

Immune checkpoint inhibitors: Monoclonal antibodies that block inhibitory pathways (e.g. PD-1/PD-L1) on T cells to restore anti-tumour immunity.

Neoantigen: A tumour-specific peptide arising from somatic mutation, recognised as non-self by the immune system.

Tumour microenvironment (TME): The cellular and molecular milieu surrounding tumour cells, including immune, stromal and vascular components.

Tumour-associated macrophages (TAMs): Macrophages infiltrating tumours that can adopt pro- or anti-tumour phenotypes depending on context.

γδ T cells: A subset of T lymphocytes bearing a distinct T-cell receptor, capable of recognising stress-induced ligands and phosphoantigens independently of classical antigen presentation.

References

1. Pediatric pan-central nervous system tumor analysis of immune-cell infiltration identifies correlates of antitumor immunity. Nature Communications (2020).
2. A H3K27M-targeted vaccine in adults with diffuse midline glioma. Nature Medicine (2023).
3. Tumour-associated macrophages exhibit anti-tumoural properties in Sonic Hedgehog medulloblastoma. Nature Communications (2019).
4. The tumor micro-environment in pediatric glioma: friend or foe?. Frontiers in Immunology (2023).
5. Liquid biopsy-based identification of prognostic and immunotherapeutically relevant gene signatures in lower grade glioma. Journal of Big Data (2023).
6. EphA2 and phosphoantigen-mediated selective killing of medulloblastoma by γδT cells preserves neuronal and stem cell integrity. OncoImmunology (2025).