Citations

Abstract Case Description: A 73-year-old female with history of stage IIIC high-grade mixed endometroid and serous ovarian cancer in remission presented with lower extremity weakness and paresthesias for several months ultimately wheelchair bound by presentation. Her exam was notable for severe proximal greater than distal lower extremity weakness, allodynia, absent patellar and Achilles reflexes, and diminished vibration and pinprick sensation. MRI demonstrated symmetric enhancement of the spinocerebellar tracts in the lateral cord from T6-T9. EMG showed a length-dependent axonal predominant sensorimotor neuropathy. The differential included metabolic, paraneoplastic, or inflammatory etiologies of her myelopathy. CSF studies revealed TNCs 30, elevated kappa free light chain, and negative cytology. Autoimmune/paraneoplastic myelopathy panels were negative. With her past history of cancer, FDG PET performed showed a right hypermetabolic chest wall and upper abdominal mass. Core needle biopsy demonstrated recurrence of high-grade carcinoma of mullerian origin consistent with recurrence of ovarian cancer. Her in-hospital treatment included 5 days of 1g IV methylprednisolone and seven sessions of PLEX. Her exam improved following PLEX with improvements in strength, sensation, and neurogenic bowel and bladder. She also started Carboplatin and Doxorubicin chemotherapy prior to discharge. She continued 60mg prednisone after discharge. She unfortunately had many hospitalizations for infections and anemia impacting her neurological recovery and strength has declined. Discussion: This case illustrates an interesting case of paraneoplastic myelopathy as the presenting symptom for relapsed ovarian cancer previously in remission for more than 10 years. The case shows the importance of keeping a paraneoplastic process on the differential when imaging findings and clinical syndrome are consistent with a paraneoplastic myelopathy even though the patient did not have a known, active cancer or positive antibodies identified. The work-up for malignancy is crucial as cancer-specific therapy is needed for hopeful symptom improvement.

Abstract BACKGROUND Diffuse midline gliomas (DMGs) and posterior fossa group A (PFA) ependymomas are aggressive pediatric brain tumors. Most DMGs harbor histone H3.3K27M or G34R mutations, or exhibit EZHIP overexpression. With a median survival of just 9–15 months, DMGs are among the most lethal human cancers. PFAs, nearly universally overexpress EZHIP and have a 5-year survival rate of ~50%. Unlike K27M or EZHIP-overexpressing DMGs, G34R-mutant tumors retain H3K27me3. METHODS Using the RCAS/Nestin-TVA system, we introduced H3.3 K27M–, G34R–, or S31A–P2A–PDGFβ or H3.3WT–P2A–PDGFβ into neonatal mice. Controls included, histone mutants EZHIP alone and ΔEZHIP (PRC2-binding-deficient). Tumor bearing mice were assessed for incidence, grade, survival, and H3K27me3 and H3.3S31P status. RESULTS H3.3K27M, G34R, and S31A–P2A–PDGFβ induced high-grade gliomas with significantly reduced survival (p < 0.001). Mechanistically, G34R—like K27M—reduced mitotic Ser31 phosphorylation (S31P), causing chromosomal instability and impaired p53 checkpoint function. S31A directly modeled loss of S31P and similarly drove high-grade tumor formation. H3.3WT–P2A–PDGFβ induced only low-grade lesions. EZHIP–P2A–PDGFβ enhanced tumor grade but not survival; only EZHIP fully abolished H3K27me3. ΔEZHIP and all unlinked constructs were non-tumorigenic. CONCLUSION These models establish a robust platform to dissect glioma drivers and chromatin vulnerabilities. We previously showed that H3.3K27M reduces S31P, promoting chromosomal instability and impaired p53 function. We now demonstrate that H3.3G34R also reduces S31P and drives tumor formation in vivo. Direct loss of S31P via H3.3S31A is likewise sufficient for gliomagenesis. Although EZHIP does not alter S31P, it promotes genome instability through distinct mechanisms—disrupting PALB2–BRCA2-mediated DNA repair and mislocalizing TopoIIα, a process dependent on H3K27me3. H3.3K27M, G34R, and EZHIP thus converge on genome instability through distinct pathways. This platform supports mechanistic and therapeutic studies and is now being expanded using tetracycline-regulated expression to investigate tumor maintenance.

Abstract Glioblastoma (GBM) progression and recurrence are often driven by therapy-resistant cellular states emerging within hypoxic tumor niches. While hypoxia is a hallmark of GBM, the spatial transcriptomic heterogeneity that underpins resistance in these regions remains poorly characterized. Here, we employ pimonidazole labeling in conjunction with high-resolution spatial and single cell transcriptomics across 29 primary, treatment-naive human GBM samples, syngeneic mouse models, and patient-derived glioma-initiating cells exposed to hypoxia to define the hypoxia-specific tumor microenvironment and its associated cellular programs. We reveal spatially organized sub-niches within hypoxic regions, each supporting diverse cellular programs yet coexisting tumor lineage states with minimal transitions between cell states. Phylogenetic reconstruction based on inferred copy number variations demonstrates consistent evolutionary trajectories from non-hypoxic to hypoxic tumor loci. Specific copy number alterations were enriched in hypoxic regions and associated with immune infiltration and poor prognosis in MGMT-methylated tumors. Cross-species analyses confirmed the conservation of hypoxia-associated gene programs and spatial architectures. Together, our study delineates the cellular, evolutionary, and spatial complexity of hypoxia in GBM, identifies hypoxia-induced genomic alterations that may promote tumor fitness, and offers insights into new therapeutic vulnerabilities within hypoxic niches.

Abstract BACKGROUND Poly(ADP-ribose) polymerase inhibitors (PARPi), initially developed for BRCA-mutant tumors, are now being explored in gliomas to target DNA repair defects. In this retrospective analysis, we report our institutional experience using PARPi with temozolomide for glioma treatment. METHODS The medical record was retrospectively reviewed at our institution for neuro-oncology patients treated with off-label PARPi combined with temozolomide for > 1 month between 1/1/2010 and 5/1/2025. RESULTS Nineteen patients (median age 45, 47% female) were included. PARPi included olaparib (n = 18) and niraparib (n = 1). Tumor types were glioblastoma (GBM, n = 7), Grade 4 IDH-mutant astrocytoma (G4A, n = 4), Grade 3 astrocytoma (G3A, n = 2), Grade 3 oligodendroglioma (G3O, n = 3), Grade 2 oligodendroglioma (G2O, n = 2), and IDH1-mutant brainstem glioma (BG, n = 1; IDH status determined per CSF 2-hydroxyglutarate without surgically confirmed histologic subtyping). Patients were heavily pre-treated. One patient lost to follow-up was censored at last contact. Patients had KPS ≥ 70 in all but one case (KPS 60) and multiple prior progressions (treatment was initiated at 4th recurrence or higher in 16/19 patients). Median time from drug initiation to progression, drug initiation to death, and overall survival were as follows (months): GBM (3.0, 6.5, 34.9), G4A (1.4, 3.9, 80.3), G3A (3.4, 4.2, 83.3), G3O (3.8, 17.2, 121.2), G2O (3.0, 3.5, 159.9), BG (4, 5.5, 164.8). CONCLUSIONS This retrospective analysis supports the tolerability of combining PARPi with temozolomide in a real-world, heavily pretreated glioma population. Despite limited evidence of durable tumor control, the regimen provided transient disease stability in patients with few remaining options. These findings may inform treatment in compassionate or salvage settings particularly when alkylator treatment is considered, and highlight the need for prospective trials to identify response biomarkers and assess clinical utility.

Abstract BACKGROUND The IDH inhibitor vorasidenib was FDA-approved for treatment of IDH-mutant grade 2 gliomas in August 2024. We evaluated vorasidenib in patients with grade 3 and 4 IDH-mutant gliomas who would not have been eligible for the INDIGO trial. METHODS Retrospective review of patients with grade 3 or 4 IDH-mutant gliomas treated with vorasidenib between 9/1/24 and 5/31/25. Prior treatments, radiographic response, adverse events and seizure control were collected for each patient. RESULTS Thirty-two patients (median age 39.5, 46.9% female) met inclusion criteria. Tumor types included grade 3 oligodendroglioma (11, 34.4%), grade 3 astrocytoma (13, 40.6%) and grade 4 astrocytoma (8, 25%). Thirty patients had contrast-enhancement; 2 patients had non-enhancing tumor. Prior treatments included surgical resection (30, 93.8%), radiation (27, 84.4%), cytotoxic chemotherapy (25, 78.1%), bevacizumab (5, 15.6%), pembrolizumab (3, 9.4%), and ivosidenib (8, 25%). Four patients (12.5%) were naïve to systemic treatment at the time of vorasidenib initiation. Median duration of vorasidenib was 101.5 days (range 18-255) with 19 patients still on vorasidenib at the time of last follow-up. Seventeen patients (53.1%) had stable disease, 11 (34.4%) had progressive disease, 2 (6.3%) did not yet have response assessment, and 2 (6.3%) died. Grade 1 transaminitis occurred in 12 patients with no high grade transaminitis. Two patients developed lymphopenia; both were heavily pre-treated with multiple alkylating agents; no other hematologic toxicity was noted. One patient developed myalgias leading to vorasidenib discontinuation. Nine patients had fatigue, 4 headaches, 2 nausea, 2 decreased appetite. In patients with a history of epilepsy, there were no reported seizures. CONCLUSIONS Vorasidenib was well-tolerated in this heavily pre-treated cohort of grade 3–4 IDH-mutant gliomas, with low-grade transaminitis and fatigue being the most common toxicities. Preliminary results show disease stability in 53.1% of patients after a median of 3.5 months. Conclusions are limited by short-interval follow-up.

Abstract Glioblastoma (GBM) is an aggressive brain tumor with poor outcomes due to resistance to radiation and temozolomide (TMZ). Death receptor 5 (DR5), a proapoptotic receptor, induces tumor-selective apoptosis upon activation, is expressed in GBM, and can be upregulated by radiation/TMZ. Ozekibart (INBRX-109), a tetravalent DR5 agonist antibody, has demonstrated tolerability and clinical benefit as monotherapy in chondrosarcoma (PMID: 37265425), prompting a phase 2 trial (NCT04950075), and in combination with irinotecan and TMZ in Ewing’s sarcoma. INBRX-109 was evaluated in GBM using in vitro and in vivo models. DR5 expression in cell lines was determined by flow cytometry and drug sensitivity was measured using CellTiter-Glo®. Efficacy of INBRX-109 as a single agent and in treatment combinations was evaluated in intracranial U87-MG and patient-derived xenograft (PDX) models with activity assessed by survival and tumor imaging. Pharmacodynamic activity was assessed by immunohistochemistry (IHC) for cleaved caspase-3 and PARP. TMZ upregulated DR5 and sensitized U87-MG cells to INBRX-109. GBM cell lines (n=33) exhibited variable sensitivity to INBRX-109 and TMZ as single agents, but a majority showed enhanced sensitivity to combination treatment. In the U87-MG model, combination therapy improved tumor control and survival versus TMZ alone (tumor volume fold increase over baseline 1.1 vs 7.4; median survival 44 vs 36d). IHC staining of tumors indicated INBRX-109 crosses the blood brain barrier and is pharmacologically active. In three PDX models, INBRX-109 improved survival as monotherapy (survival ratios 1.38, 1.47, 1.50). In two models, combination therapy improved survival vs TMZ (survival ratios 1.76 vs 0.93, 2.47 vs 1.94). In summary, TMZ upregulates DR5 and enhances INBRX-109 activity in intracranial GBM models. This combinatorial activity and potential for synergy with radiation/TMZ support clinical evaluation of INBRX-109 in GBM. Moreover, the established clinical safety and activity of INBRX-109 in solid tumors support its development in this indication.

Abstract Glioblastoma, IDH-wildtype (GBM), and primary central nervous system lymphoma (PCNSL) are two aggressive brain tumors with distinct treatment strategies but overlapping imaging features on MRI. Accurate preoperative differentiation remains a clinical challenge, due to their overlapping imaging features, even when advanced MRI techniques are employed. This study explored deep learning approaches leveraging multi-sequence MRI to distinguish GBM from PCNSL. Models were developed utilizing 146 PCNSL cases, which were matched to146 GBM by age, sex and year of diagnosis. A 3D-DenseNet121 convolutional neural network was trained using two analytical strategies: (i) loss-based model selection and (ii) ensemble prediction using five-fold cross-validation. Model performance was evaluated on an independent validation set of 256 GBM and 37 PCNSL from the same institution as well as 36 PCNSL cases from an external institution. All MRIs were preprocessed using the FeTS pipeline. Using the independent validation cohort, area under the receiver operating characteristic curve (AUC) and 95% confidence intervals (CI) were computed overall and stratified by demographic characteristics. Using both T1 post-contrast (T1Gd) and T2-weighted images, the loss-based model achieved AUC=0.83 (95% CI: 0.77-0.88) and the ensemble model yielded an AUC=0.82 (95% CI: 0.76-0.89). Model performance was similar across males and females; however, model performance was better for subjects older than 50 years of age versus younger than 50. When using only T1Gd images, the loss-based model dropped to AUC=0.55 (95% CI: 0.48-0.63), whereas the ensemble model had AUC=0.79 (95% CI: 0.72-0.85). Models trained with only T2 images achieved AUCs of 0.67 (95% CI: 0.60-0.73) (loss-based) and 0.75 (95% CI: 0.69-0.82) (ensemble). These results highlight the added value of the multi-sequence input. Our results confirm the feasibility of using automated deep learning models to differentiate GBM from PCNSL. Notably, the model generalized well to external MRI data, emphasizing its potential utility as a diagnostic aid in real-world clinical workflows.

Abstract Polyamines are small molecules that play a critical role in tumor progression and in the regulation of immune responses within the tumor microenvironment. Elevated levels of polyamines in cerebrospinal fluid and tumor tissue have been reported in multiple studies and are shown to correlate with glioma grade. These findings suggest that the polyamine metabolic pathway may represent a therapeutic target in gliomas. Difluoromethylornithine (DFMO) is an irreversible inhibitor of ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis, expected to exert antitumor effects through polyamine depletion. Although the impact of DFMO against glioblastoma as a monotherapy appears limited, opportunities for synergy with other therapies remain understudied. In this study, we evaluated the therapeutic efficacy of DFMO using both in vitro and in vivo experiments with a murine glioma model (CT-2A) and patient-derived xenograft (PDX) cell lines. Among the models tested, CT-2A cells exhibited the highest expression of ODC1 and demonstrated strong sensitivity to DFMO in vitro. We compared two CT-2A variants: a commercially available line responsive to immunotherapy, and a widely used subline resistant to PD-1 blockade. While DFMO did not improve survival in mice implanted with the immunotherapy-sensitive commercial CT-2A line, it extended median survival by 8 days in mice bearing tumors derived from the immunotherapy-resistant subline. Transcriptomic analysis revealed that the DFMO-responsive, immunotherapy-resistant tumors exhibited lower baseline expression of immune-related genes, including those involved in interferon-β, interferon-γ, and IL-12 signaling pathways, compared to the immunotherapy-sensitive tumors. The latter showed markedly higher expression of STAT1 and interferon-γ and were enriched for immune-related Gene Ontology terms. These findings suggest that polyamine-targeted therapy may be appropriate for gliomas with an immunosuppressive, “cold” phenotype. Ongoing RNA sequencing analyses aim to further elucidate the immunomodulatory mechanisms of DFMO, and other agents comprising an adaptive toolkit to optimize and sustain anti-tumoral immunity.

Abstract BACKGROUND Many cancers demonstrate upregulated amino acid transport. In glioblastoma (GBM), evidence for upregulated amino acid flux includes high signal on amino acid PET imaging, increased expression of LAT1 (L-type amino acid transporter 1), and elevated extracellular amino acid levels via microdialysis. LAT1-targeted therapies have shown antitumor effects in certain cancer models by restricting essential amino acid supply and inhibiting the mTOR pathway, but their utility for GBM remains unknown. In this study, we evaluated impacts of a competitive LAT1 inhibitor, nanvuranlat, and a non-competitive inhibitor, JPH034 against glioblastoma. METHODS Murine (CT-2A, GL261) and human (GBM6, GBM39) GBM cell lines were tested under varying concentrations of nanvuranlat or JPH034. The competitive impacts of added essential amino acids, serum, and albumin were evaluated in vitro. Survival impacts were evaluated in an intracranial CT-2A glioma model. RESULTS Supplementing essential amino acids in vitro significantly decreased tumor cell sensitivity to nanvuranlat but did not change the IC50 of JPH034. Conversely, supplementing serum or albumin significantly reduced tumor cell sensitivity to JPH034 but did not change the IC50 of nanvuranlat. These findings were reproducible in all human and murine cell lines tested. In the intracranial mouse model, JPH034 treatment prolonged median overall survival from 16 days in the control group to 18.5 days, representing a 2.5-day extension (p = 0.060). CONCLUSION The antitumor effects of nanvuranlat and JPH034 on glioma cells in vitro, are influenced by concentrations of essential amino acids and albumin. Specifically, amino acids decreased impact of the competitive inhibitor (nanvuranlat) while albumin decreased impact of the non-competitive inhibitor (JPH034). These results suggest that the composition of the tumor microenvironment, which is impacted by BBB-disruption within GBM may differentially attenuate the therapeutic efficacy of certain drugs including LAT1 inhibitors.

Abstract Glioblastoma (GBM) diagnosis integrates morphology and tumor molecular alterations. Patients with classic morphology are designated as histologic GBM (hGBM). Patients without classic morphology harboring TERT promoter mutation (TERTp), or epidermal growth factor receptor amplification (EGFRamp), or combined gain of chromosome 7 and loss of 10 (+7/-10) designate molecular GBM (mGBM). We compared radiographic features, genomic alterations, and clinical outcome between hGBM and mGBM. 109 mGBM Mayo Clinic cases diagnosed between 1993-2021 were matched to 101 cGBM by age, sex, year of diagnosis, and TERT promoter (TERTp) status. Clinical and radiographic data abstraction was blinded. Progression-free and overall survival were compared across groups in the subset of patients who received standard of care. Contrast enhancement was present on index MRI (MRI at diagnosis) for 98% (96/98) hGBM and 50% (54/107) mGBM (p<0.0001) patients. mGBM tumors harbored fewer total copy number alterations (median of 16.5 vs 20, p=0.029) and were less likely to have CDKN2A/B homozygous deletion (56% vs 77%, p=0.005). Among the 87 mGBM and 82 hGBM receiving standard of care, median overall survival was longer for mGBM versus hGBM (2.24 vs 1.62 years, p=0.016). mGBM patients with +7/-10 (HR=2.60, p=0.035) or CDKN2A/B (HR=3.61, p=0.002) had poorer overall survival compared to mGBM patients without the corresponding alteration. On index MRI mGBM patients without contrast enhancement had better overall survival compared to hGBM (HR=0.50; p=0.003) whereas there was no survival difference between mGBM with enhancement and hGBM. mGBM with enhancement on index MRI likely represent undersampled, or early / evolving hGBM. mGBM patients with non-enhancing MRI, younger than 60, with long symptom profile including seizures, and some combination of non-anaplastic morphology, TERTp only, no homozygous deletion of CDKN2A/B, and low copy number complexity may represent other IDHwt glioma entities. Caution is advised in counseling, management, discussing prognosis, and inclusion in clinical trials.