Primary brain and central nervous system (CNS) tumors are a diverse group of neoplasms that occur within the brain and spinal cord. Although significant advances in our understanding of the intricate biological underpinnings of CNS neoplasm tumorigenesis and progression have been made, the translation of these discoveries into effective therapies has been stymied by the unique challenges presented by these tumors’ exquisitely sensitive location and the body’s own defense mechanisms (e.g., the brain–CSF barrier and blood–brain barrier), which normally protect the CNS from toxic insult. These barriers effectively prevent the delivery of therapeutics to the site of disease. To overcome these obstacles, new methods for therapeutic delivery are being developed, with one such approach being the utilization of nanoparticles. Here, we will cover the current state of the field with a particular focus on the challenges posed by the BBB, the different nanoparticle classes which are under development for targeted CNS tumor therapeutics delivery, and strategies which have been developed to bypass the BBB and enable effective therapeutics delivery to the site of disease.

Medulloblastoma is the most common malignant brain tumor in children. Over the last few decades, significant progress has been made in revealing the key molecular underpinnings of this disease, leading to the identification of distinct molecular subgroups with different clinical outcomes. In this review, we provide an update on the molecular landscape of medulloblastoma and treatment strategies. We discuss the four main molecular subgroups (WNT-activated, SHH-activated, and non-WNT/non-SHH groups 3 and 4), highlighting the key genetic alterations and signaling pathways associated with each entity. Furthermore, we explore the emerging role of epigenetic regulation in medulloblastoma and the mechanism of resistance to therapy. We also delve into the latest developments in targeted therapies and immunotherapies. Continuing collaborative efforts are needed to further unravel the complex molecular mechanisms and profile optimal treatment for this devastating disease.

Background: T cell-based immunotherapies have had limited success in glioma thus far. Here, we evaluate the literature on abundance, spatial distribution and phenotypical characteristics of T cells in the tumor micro-environment (TME) of IDH-mutant and IDH-wildtype glioma, with the aim to understand how these measures relate to immunotherapy resistance and to aid the development of immunotherapies for glioma. Methods: Medline, Embase, Web of Science Core Collection, Google Scholar and the Cochrane Central Register of Controlled Trials were systematically searched up to May 6, 2025. Out of 4303 articles screened, 85 studies examining T cell immunity in human glioma were selected. We collected information about tumor subtype, grade, methods, T cell abundance, spatial distribution, phenotypes and prognostic significance. Results: T cells are present in the glioma TME, but densities are heterogeneous and generally low, especially in IDH-mutant glioma. T cell abundance increases with higher WHO grade and upon recurrence. T cells cluster around blood vessels, especially in IDH-mutant glioma. Glioma-infiltrating T cells largely display a late-differentiated phenotype (CD45RA-CCR7-C62L-), expressing markers that signify sustained antigen activation and exhaustion (PD-1, CTLA-4, TIM-3, LAG-3, CD39, and TIGIT). This phenotype coincides with decreased anti-tumor cytotoxicity and is spatially enriched in the myeloid-rich, hypoxic tumor core. Prognostic significance remains controversial. Conclusions: T cells in glioma are scarce, generally fully differentiated and functionally inert. Understanding and reinvigorating the deficient T cell response will be essential for successful immunotherapies. Future research should incorporate functional and spatial immune profiling to optimize and personalize immunotherapeutic strategies for glioma patients.

Radiotherapy (RT) is the standard-of-care for diffuse intrinsic pontine glioma (DIPG); however, it functions as a palliative treatment. Interleukin 13 receptor subunit alpha 2 (IL-13Rα2) is upregulated in most DIPG tumors, posing a promising therapeutic target. Immunotherapies harnessing IL-13Rα2 to selectively deliver cytotoxic payloads such as pseudomonas exotoxin A (PE) are safe in DIPG patients and efficacious in preclinical disease models. Here, we used DIPG cell lines and mouse models to compare RT alone with RT plus the IL-13Rα2-targeted PE immunotoxin GB13 (IL13.E13K-PE4E). DNA strand breaks were evaluated by γH2AX and apoptosis, as well as other on-target effects, by Western blot and immunofluorescence. Cell viability and colony formation assays delineated cell viability and proliferation. In vivo efficacy was based on survival of mice with orthotopic tumors. Animals received fractionated focal irradiation and neoadjuvant and concomitant GB13 by convection-enhanced delivery. GB13 improved the efficacy of RT in vitro through inhibition of DNA damage repair and convergent modulation of apoptotic signaling. Combined RT and intratumoral administration of GB13 decreased tumor burden and prolonged survival in orthotopic xenograft and genetically engineered mouse models. These findings indicate that RT plus GB13 is well tolerated and effective, informing future investigation of a novel therapeutic approach for DIPG.