Faculty Bibliography

Decreased brain levels of coenzyme Q₁₀ (CoQ₁₀), an endogenously synthesized lipophilic antioxidant^1,2, underpin encephalopathy in primary CoQ₁₀ deficiencies^3,4 and are associated with common neurodegenerative diseases and the ageing process^5,6. CoQ₁₀ supplementation does not increase CoQ₁₀ pools in the brain or in other tissues. The recent discovery of the mammalian CoQ₁₀ headgroup synthesis pathway, in which 4-hydroxyphenylpyruvate dioxygenase-like protein (HPDL) makes 4-hydroxymandelate (4-HMA) to synthesize the CoQ₁₀ headgroup precursor 4-hydroxybenzoate (4-HB)⁷, offers an opportunity to pharmacologically restore CoQ₁₀ synthesis and mechanistically treat CoQ₁₀ deficiencies. To test whether 4-HMA or 4-HB supplementation promotes CoQ₁₀ headgroup synthesis in vivo, here we administered 4-HMA and 4-HB to Hpdl^-/- mice, which model an ultra-rare, lethal mitochondrial encephalopathy in humans. Both 4-HMA and 4-HB were incorporated into CoQ₉ and CoQ₁₀ in the brains of Hpdl^-/- mice. Oral treatment of Hpdl^-/- pups with 4-HMA or 4-HB enabled 90-100% of Hpdl^-/- mice to live to adulthood. Furthermore, 4-HB treatment stabilized and improved the neurological symptoms of a patient with progressive spasticity due to biallelic HPDL variants. Our work shows that 4-HMA and 4-HB can modify the course of mitochondrial encephalopathy driven by HPDL variants and demonstrates that CoQ₁₀ headgroup intermediates can restore CoQ₁₀ synthesis in vivo.

PURPOSE/OBJECTIVE:) disease. NRG Oncology BN002 (phase I) demonstrated safety and suggested efficacy of ipilimumab (ipi) with nivolumab (nivo) in newly diagnosed glioblastoma, leading to this phase II/III trial. METHODS:) of .15, superior PFS with immunotherapy in phase II would lead to phase III overall survival (OS) testing. Corticosteroids were disallowed when starting immunotherapy. Diagnosis, biomarkers, and PFS were centrally assessed. RESULTS:= .36). CONCLUSION/CONCLUSIONS:glioblastoma versus TMZ. Accrual closed permanently; the trial will not proceed to phase III. No new safety signals were identified. Molecular correlative analyses and survival follow-up are ongoing.

BACKGROUND:Diffuse hemispheric glioma, histone 3 (H3) G34-mutant, has been newly defined in the 2021 WHO classification of central nervous system tumors. Here we sought to define the prognostic roles of clinical, neuroimaging, pathological, and molecular features of these tumors. METHODS:We retrospectively assembled a cohort of 114 patients (median age 22 years) with diffuse hemispheric glioma, H3 G34-mutant, CNS WHO grade 4 and profiled the imaging, histological and molecular landscape of their tumors. RESULTS:Compared with glioblastoma, H3 G34-mutant diffuse hemispheric gliomas exhibited less avid contrast enhancement, necrosis and edema on MRI. Comprehensive analyses of mutational and DNA copy number profiles revealed recurrent mutations in TP53 and ATRX, homozygous deletions of CDKN2A/B, and amplifications of PDGFRA, EGFR, CCND2, and MYCN. MGMT promoter methylation was detected in 79 tumors (75%); 11 tumors (13%) showed DNA copy number profiles suggestive of circumscribed deletions on 10q26.3 involving the MGMT locus. Median survival was 21.5 months. Female sex, gross total resection, and MGMT promoter methylation were positive prognostic factors on univariate analysis. Among radiological, pathological and molecular features, absence of pial invasion, and presence of microvascular proliferation and CDK6 amplification were positive prognostic factors on univariate analyses. CONCLUSIONS:This study refines the clinical and molecular landscape of H3 G34-mutant diffuse hemispheric gliomas. Dedicated trials for this novel tumor type are urgently needed.

BACKGROUND:Accurate intraoperative diagnosis is crucial for differentiating between primary CNS lymphoma (PCNSL) and other CNS entities, guiding surgical decision-making, but represents significant challenges due to overlapping histomorphological features, time constraints, and differing treatment strategies. We combined stimulated Raman histology (SRH) with deep learning to address this challenge. METHODS:We imaged unprocessed, label-free tissue samples intraoperatively using a portable Raman scattering microscope, generating virtual H&E-like images within less than three minutes. We developed a deep learning pipeline called RapidLymphoma based on a self-supervised learning strategy to (1) detect PCNSL, (2) differentiate from other CNS entities, and (3) test the diagnostic performance in a prospective international multicenter cohort and two additional independent test cohorts. We trained on 54,000 SRH patch images sourced from surgical resections and stereotactic-guided biopsies, including various CNS neoplastic/non-neoplastic lesions. Training and test data were collected from four tertiary international medical centers. The final histopathological diagnosis served as ground-truth. RESULTS:In the prospective test cohort of PCNSL and non-PCNSL entities (n=160), RapidLymphoma achieved an overall balanced accuracy of 97.81% ±0.91, non-inferior to frozen section analysis in detecting PCNSL (100% vs. 77.77%). The additional test cohorts (n=420, n=59) reached balanced accuracy rates of 95.44% ±0.74 and 95.57% ±2.47 in differentiating IDH-wildtype diffuse gliomas and various brain metastasis from PCNSL. Visual heatmaps revealed RapidLymphoma's capabilities to detect class-specific histomorphological key features. CONCLUSIONS:RapidLymphoma proves reliable and valid for intraoperative PCNSL detection and differentiation from other CNS entities. It provides visual feedback within three minutes, enabling fast clinical decision-making and subsequent treatment strategy planning.

Somatic-type malignancies (SMs) arising in germ cell tumors (GCTs) are aggressive neoplasms resistant to systemic treatment. Most are diagnosed in metastatic sites after chemotherapy; however, they have also been well-documented in primary testicular GCTs. Historically, SMs were thought to originate in components of teratoma that acquire molecular alterations equivalent to those that characterize their true somatic counterparts. However, recent studies have shown that SMs typically lack the hallmark molecular alterations seen in similar somatic tumors. Additionally, clinicopathologic and molecular data suggest that a subset may derive from yolk sac tumor (YST) rather than teratoma. In this study, we evaluated the relationship between conventional histological types of GCTs and SMs by comparing expression of microRNA (miR)-371-373 and genomic methylation profiles. A total of 96 samples (including multiple paired conventional GCT-SM samples from individual tumors) were assessed for miR-371-373 expression by RT-qPCR and genomic DNA methylation using a clinically validated assay. Expression of miR-371-373 was higher in conventional GCTs than in SMs (considered as a single category encompassing all histological subtypes). However, miR-371-373 expression was heterogeneous among SMs, with significantly higher levels in sarcomatoid YST (SYST) and glandular neoplasms than in other SMs. Genomic DNA methylation analysis showed that SMs (considered as a single category) did not form a distinct cluster. Instead, they grouped into multiple clusters that did not show perfect correspondence with histology and often included conventional GCTs. Genome-wide methylation assessment showed a higher abundance of hypermethylated regions in SMs than in conventional GCTs. Analysis of paired conventional GCT and 'somatic-type' components that did not meet size criteria for SMs dissected from individual tumors demonstrated separation according to histology, suggesting that epigenetic processes play a role in the transition from conventional GCT to 'somatic-type' phenotypes. Gene-level and pathway-level analyses identified MAPK/RAS signaling, mitosis/proliferation, differentiation towards neural tissue/neuroectoderm, epithelial-to-mesenchymal transition, and DNA repair as key differentially regulated processes in components with somatic-type histology, suggesting mechanisms of progression from conventional to 'somatic' phenotypes in GCT. These results support the hypothesis that a subset of SMs derive from YST and suggest that some subtypes (such as SYST) may represent 'intermediate' phenotypes. Additionally, analysis of differentially methylated promoter regions in SM identified genes and biologic processess that may underlie 'somatic tranformation' in GCTs. © 2025 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

BACKGROUND:Intracerebral schwannomas are rare tumors resembling their peripheral nerve sheath counterparts but localized in the CNS. They are not classified as a separate tumor type in the 2021 WHO classification. This study aimed to compile and characterize these rare neoplasms morphologically and molecularly. METHODS:We analyzed 20 tumor samples by histology, RNA Next-Generation Sequencing, DNA-methylation profiling, copy number analyses, and single nucleus RNA sequencing (snRNA-seq). Clinical data, including age, sex, and disease progression, were collected. MRI series were included when available. RESULTS:All cases with tissue available for histology review (n=13) were morphologically consistent with intracerebral schwannoma, but differed in their extent of GFAP staining. All (n=20) shared DNA-methylation profiles distinct from other CNS tumors, as well as from VGLL-altered peripheral nerve sheath tumors. Most cases (n=14/17) harbored fusions of either VGLL3 or VGLL1 (CHD7::VGLL3 (n=9/17) and EWSR1::VGLL1 (n=5/17)). In two cases the presence of a VGLL3 fusion was also confirmed by CNA analyses (n=2/17). MRI (n=4) showed well-defined, nodular tumors with strong, homogeneous enhancement and no diffusion restriction. Tumors were located throughout the neuroaxis [supratentorial (n=15), infratentorial (n=4), and spinal (n=1)]. snRNA-seq of a VGLL1-fused tumor indicated VGLL1 upregulation in 28.6% of tumor cells (n=1). During median follow-up of 1.8 years (range 3 months-9 years), none of the tumors recurred (n=10). CONCLUSIONS:We identify and define a new benign tumor class, designated VGLL-altered intraparenchymal CNS schwannomas. These tumors feature VGLL alterations and a specific DNA-methylation profile, with schwannoma-like histopathology and CNS localization, akin to previously classified intracerebral schwannomas.

Chromosomal structural variants (SVs) are major contributors to cancer development. Although multiple methods exist for detecting SVs, they are limited in throughput, such as fluorescent in situ hybridization and targeted panels, and use RNA, which degrades in formalin-fixed, paraffin-embedded (FFPE) blocks and is unable to detect SVs that do not produce a fusion transcript. High-throughput chromosome conformation capture (Hi-C) is a DNA-based next-generation sequencing (NGS) method that preserves the spatial conformation of the genome, capturing long-range genetic interactions and SVs. Herein, a retrospective study analyzing 71 FFPE specimens from 10 different solid tumors was performed. Results showed high concordance (98%) with clinical fluorescent in situ hybridization and RNA NGS in detecting known SVs. Furthermore, Hi-C provided insight into the mechanism of SV formation, including chromothripsis and extrachromosomal DNA, and detected rearrangements between genes and regulatory regions, all of which are undetectable by RNA NGS. Lastly, SVs were detected in 71% of cases in which previous clinical methods failed to identify a driver. Of these, 14% were clinically actionable based on current medical guidelines, and an additional 14% were not in medical guidelines but involve targetable biomarkers. Current data suggest that Hi-C is a robust and accurate method for genome-wide SV analyses from FFPE tissue and can be incorporated into current clinical NGS workflows.