A clinically applicable integrative molecular classification of meningiomas.

Meningiomas are the most common primary intracranial tumour in adults1. Patients with symptoms are generally treated with surgery as there are no effective medical therapies. The World Health Organization histopathological grade of the tumour and the extent of resection at surgery (Simpson grade) are associated with the recurrence of disease; however, they do not accurately reflect the clinical behaviour of all meningiomas2. Molecular classifications of meningioma that reliably reflect tumour behaviour and inform on therapies are required. Here we introduce four consensus molecular groups of meningioma by combining DNA somatic copy-number aberrations, DNA somatic point mutations, DNA methylation and messenger RNA abundance in a unified analysis. These molecular groups more accurately predicted clinical outcomes compared with existing classification schemes. Each molecular group showed distinctive and prototypical biology (immunogenic, benign NF2 wild-type, hypermetabolic and proliferative) that informed therapeutic options. Proteogenomic characterization reinforced the robustness of the newly defined molecular groups and uncovered highly abundant and group-specific protein targets that we validated using immunohistochemistry. Single-cell RNA sequencing revealed inter-individual variations in meningioma as well as variations in intrinsic expression programs in neoplastic cells that mirrored the biology of the molecular groups identified.

Multiplatform molecular analysis of vestibular schwannoma reveals two robust subgroups with distinct microenvironment.

BACKGROUND: Vestibular schwannoma (VS) is the most common tumour of the cerebellopontine angle and poses a significant morbidity for patients. While many exhibit benign behaviour, others have a more aggressive nature and pattern of growth. Predicting who will fall into which category consistently remains uncertain. There is a need for a better understanding of the molecular landscape, and important subgroups therein, of this disease. METHODS: We select all vestibular schwannomas from our tumour bank with both methylation and RNA profiling available. Unsupervised clustering methods were used to define two distinct molecular subgroups of VS which were explored using computational techniques including bulk deconvolution analysis, gene pathway enrichment analysis, and drug repurposing analysis. Methylation data from two other cohorts were used to validate our findings, given a paucity of external samples with available multi-omic data. RESULTS: A total of 75 tumours were analyzed. Consensus clustering and similarity network fusion defined two subgroups ("immunogenic" and "proliferative") with significant differences in immune, stroma, and tumour cell abundance (p < 0.05). Gene network analysis and computational drug repurposing found critical differences in targets of immune checkpoint inhibition PD-1 and CTLA-4, the MEK pathway, and the epithelial to mesenchymal transition program, suggesting a need for subgroup-specific targeted treatment/trial design in the future. CONCLUSIONS: We leverage computational tools with multi-omic molecular data to define two robust subgroups of vestibular schwannoma with differences in microenvironment and therapeutic vulnerabilities.

Current state of therapeutic focused ultrasound applications in neuro-oncology.

INTRODUCTION: Despite manifold advances in oncology, cancers of the central nervous system remain among the most lethal. Unique features of the brain, including distinct cellular composition, immunological privilege, and physical barriers to therapeutic delivery, likely contribute to the poor prognosis of patients with neuro-oncological disease. Focused ultrasound is an emerging technology that allows transcranial delivery of ultrasound energy to focal brain targets with great precision. METHODS: A review of the clinical and preclinical focused ultrasound literature was performed to obtain data regarding the current state of the focused ultrasound in context of neuro-oncology. A narrative review was then constructed to provide an overview of current and future applications of this technology. RESULTS: Focused ultrasound can facilitate direct control of tumors by thermal or mechanical ablation, as well as enhance delivery of diverse therapeutics by disruption of the blood-brain barrier without local tissue damage. Indeed, ultrasound-sensitive drug formulations or sonosensitizers may be combined with ultrasound blood-brain barrier disruption to achieve high local drug concentration while limiting systemic exposure to therapeutics. Furthermore, focused ultrasound can induce radiosensitization, immunomodulation, and neuromodulation. Here we review applications of focused ultrasound with a focus on approaches currently under clinical investigation for the treatment of neuro-oncological disease, such as blood-brain barrier disruption for drug delivery and thermal ablation. We also discuss design of clinical trials, selection of patient cohorts, and emerging approaches to improve the efficacy of transcranial ultrasound, such as histotripsy, as well as combinatorial strategies to exploit synergistic biological effects of existing cancer therapies and ultrasound. CONCLUSIONS: Focused ultrasound is a promising and actively expanding therapeutic modality for diverse neuro-oncological diseases.

Epigenomic, genomic, and transcriptomic landscape of schwannomatosis.

Schwannomatosis (SWNTS) is a genetic cancer predisposition syndrome that manifests as multiple and often painful neuronal tumors called schwannomas (SWNs). While germline mutations in SMARCB1 or LZTR1, plus somatic mutations in NF2 and loss of heterozygosity in chromosome 22q have been identified in a subset of patients, little is known about the epigenomic and genomic alterations that drive SWNTS-related SWNs (SWNTS-SWNs) in a majority of the cases. We performed multiplatform genomic analysis and established the molecular signature of SWNTS-SWNs. We show that SWNTS-SWNs harbor distinct genomic features relative to the histologically identical non-syndromic sporadic SWNs (NS-SWNS). We demonstrate the existence of four distinct DNA methylation subgroups of SWNTS-SWNs that are associated with specific transcriptional programs and tumor location. We show several novel recurrent non-22q deletions and structural rearrangements. We detected the SH3PXD2A-HTRA1 gene fusion in SWNTS-SWNs, with predominance in LZTR1-mutant tumors. In addition, we identified specific genetic, epigenetic, and actionable transcriptional programs associated with painful SWNTS-SWNs including PIGF, VEGF, MEK, and MTOR pathways, which may be harnessed for management of this syndrome.

Evidence of small-fiber neuropathy in neurofibromatosis type 1.

INTRODUCTION: Large-fiber neuropathy is rare in neurofibromatosis type 1, but small-fiber neuropathy has not been studied. METHODS: Patients with neurofibromatosis type 1 underwent nerve conduction studies for large-fiber assessment. Small-fiber tests included quantitative thermal thresholds, laser Doppler flare imaging, intraepidermal nerve fiber density, and corneal nerve fiber length. RESULTS: Of the 52 patients enrolled, 31 (60%) were female and the mean age was 33.0 ± 12.3 years. Four (8%) patients had abnormal nerve conduction studies. Small-fiber tests were frequently abnormal: thermal thresholds in 7 (13%); laser Doppler flare imaging in 10 (19%); intraepidermal nerve fiber density in 11 (22%); and corneal nerve fiber length in 27 (52%). The mean corneal nerve fiber length was below normative level (10.1 ± 2.7 mm/mm3 ). DISCUSSION: Small-fiber neuropathy may be common in neurofibromatosis type 1, and should be investigated in symptomatic patients.

Treatment of a Patient With Task-Specific Writing Tremor Using Magnetic Resonance-Guided Focused Ultrasound.

Task-specific dystonia is characterized by abnormal repetitive movements or postures in a specific body part that is triggered and ends with a task, such as writing. Failing medications, surgery, specifically disruption of key nuclei in the thalamus, can provide excellent symptomatic relief. Transcranial magnetic resonance (MR)-guided focused ultrasound is an emerging incision-less thermoablation technique. We describe MR-guided focused ultrasound tandem ablation of the ventral intermediate and ventralis oralis posterior nuclei in a 60-year-old patient with writer's cramp. The clinical improvement was immediate with incremental benefit from the latter lesion, which was sustained at 6 months follow-up.

Multiplatform molecular profiling uncovers two subgroups of malignant peripheral nerve sheath tumors with distinct therapeutic vulnerabilities.

Malignant peripheral nerve sheath tumor (MPNST) is a highly aggressive sarcoma, and a lethal neurofibromatosis type 1-related malignancy, with little progress made on treatment strategies. Here, we apply a multiplatform integrated molecular analysis on 108 tumors spanning the spectrum of peripheral nerve sheath tumors to identify candidate drivers of MPNST that can serve as therapeutic targets. Unsupervised analyses of methylome and transcriptome profiles identify two distinct subgroups of MPNSTs with unique targetable oncogenic programs. We establish two subgroups of MPNSTs: SHH pathway activation in MPNST-G1 and WNT/ß-catenin/CCND1 pathway activation in MPNST-G2. Single nuclei RNA sequencing characterizes the complex cellular architecture and demonstrate that malignant cells from MPNST-G1 and MPNST-G2 have neural crest-like and Schwann cell precursor-like cell characteristics, respectively. Further, in pre-clinical models of MPNST we confirm that inhibiting SHH pathway in MPNST-G1 prevent growth and malignant progression, providing the rational for investigating these treatments in clinical trials.

Bullseye EVD: preclinical evaluation of an intra-procedural system to confirm external ventricular drainage catheter positioning.

PURPOSE: External ventricular drainage (EVD) is a life-saving procedure indicated for elevated intracranial pressure. A catheter is inserted into the ventricles to drain cerebrospinal fluid and release the pressure on the brain. However, the standard freehand EVD technique results in catheter malpositioning in up to 60.1% of procedures. This proof-of-concept study aimed to evaluate the registration accuracy of a novel image-based verification system "Bullseye EVD" in a preclinical cadaveric model of catheter placement. METHODS: Experimentation was performed on both sides of 3 cadaveric heads (n = 6). After a pre-interventional CT scan, a guidewire simulating the EVD catheter was inserted as in a clinical EVD procedure. 3D structured light images (Einscan, Shining 3D, China) were acquired of an optical tracker placed over the guidewire on the surface of the scalp, along with three distinct cranial regions (scalp, face, and ear). A computer vision algorithm was employed to determine the guidewire position based on the pre-interventional CT scan and the intra-procedural optical imaging. A post-interventional CT scan was used to validate the performance of the Bullseye optical imaging system in terms of trajectory and offset errors. RESULTS: Optical images which combined facial features and exposed scalp within the surgical field resulted in the lowest trajectory and offset errors of 1.28° ± 0.38° and 0.33 ± 0.19 mm, respectively. Mean duration of the optical imaging procedure was 128 ± 35 s. CONCLUSIONS: The Bullseye EVD system presents an accurate patient-specific method to verify freehand EVD positioning. Use of facial features was critical to registration accuracy. Workflow automation and development of a user interface must be considered for future clinical evaluation.

Consensus core clinical data elements for meningiomas (v2021.1).

BACKGROUND: With increasing molecular analyses of meningiomas, there is a need to harmonize language used to capture clinical data across centers to ensure that molecular alterations are appropriately linked to clinical variables of interest. Here the International Consortium on Meningiomas presents a set of core and supplemental meningioma-specific common data elements (CDEs) to facilitate comparative and pooled analyses. METHODS: The generation of CDEs followed the 4-phase process similar to other National Institute of Neurological Disorders and Stroke (NINDS) CDE projects: discovery, internal validation, external validation, and distribution. RESULTS: The CDEs were organized into patient- and tumor-level modules. In total, 17 core CDEs (10 patient level and 7 tumor level) as well as 14 supplemental CDEs (7 patient level and 7 tumor level) were defined and described. These CDEs are now made publicly available for dissemination and adoption. CONCLUSIONS: CDEs provide a framework for discussion in the neuro-oncology community that will facilitate data-sharing for collaborative research projects and aid in developing a common language for comparative and pooled analyses. The meningioma-specific CDEs presented here are intended to be dynamic parameters that evolve with time and The Consortium welcomes international feedback for further refinement and implementation of these CDEs.

MR-guided focused ultrasound enhances delivery of trastuzumab to Her2-positive brain metastases.

The blood-brain barrier (BBB) is an important factor limiting the effectiveness of central nervous system (CNS) therapeutics. MR-guided focused ultrasound (MRgFUS) is a noninvasive, spatially precise technology that enhances drug delivery across a temporarily permeable BBB. However, despite promising preclinical data, successful drug delivery has yet to be proven in human patients. In this study, we provide primary evidence of enhanced brain penetration of trastuzumab with MRgFUS in patients with Her2-positive breast cancer and brain metastases (NCT03714243). Four patients with progressive intracranial disease and stable systemic disease were enrolled in a single-arm open-labeled study. Twenty treatments combining transcranial MRgFUS with concomitant standard-of-care intravenous trastuzumab-based therapies were administered as outpatient procedures. The primary outcome was safety, and there were no treatment-related serious adverse events. The efficacy of trastuzumab delivery was demonstrated using 111In-BzDTPA-NLS-trastuzumab SPECT imaging. The standardized uptake value ratio (SUVR) of MRgFUS-treated lesions increased, on average, by 101 ± 71%, compared to −18 ± 26% in control lesions. MRgFUS enhanced drug uptake in 87 ± 17% of sonicated voxels (>20% increase in SUVR), with up to a 450% voxel-wise increase detected. Control lesions had 8 ± 8% voxels with >20% increase in SUVR. With treatment, unidimensional tumor measurements decreased by 19 ± 12%. This study provides first-in-human evidence of noninvasive, spatially targeted monoclonal antibody delivery across the BBB using MRgFUS, demonstrating the promise of this technology for a broad range of CNS diseases.

MR-guided focused ultrasound liquid biopsy enriches circulating biomarkers in patients with brain tumors.

BACKGROUND: Liquid biopsy is promising for early detection, monitoring of response, and recurrence of cancer. The blood-brain barrier (BBB) limits the shedding of biomarker, such as cell-free DNA (cfDNA), into the blood from brain tumors, and their detection by conventional assays. Transcranial MR-guided focused ultrasound (MRgFUS) can safely and transiently open the BBB, providing an opportunity for less-invasive access to brain pathology. We hypothesized that MRgFUS can enrich the signal of circulating brain-derived biomarkers to aid in liquid biopsy. METHODS: Nine patients were treated in a prospective single-arm, open-label trial to investigate serial MRgFUS and adjuvant temozolomide combination in patients with glioblastoma (NCT03616860). Blood samples were collected as an exploratory measure within the hours before and after sonication, with control samples from non-brain tumor patients undergoing BBB opening (BBBO) alone (NCT03739905). RESULTS: Brain regions averaging 7.8 ± 6.0 cm3 (range 0.8-23.1 cm3) were successfully treated within 111 ± 39 minutes without any serious adverse events. We found MRgFUS acutely enhanced plasma cfDNA (2.6 ± 1.2-fold, P < .01, Wilcoxon signed-rank test), neuron-derived extracellular vesicles (3.2 ± 1.9-fold, P < .01), and brain-specific protein S100b (1.4 ± 0.2-fold, P < .01). Further comparison of the cfDNA methylation profiles suggests a signature that is disease- and post-BBBO-specific, in keeping with our hypothesis. We also found cfDNA-mutant copies of isocitrate dehydrogenase 1 (IDH1) increased, although this was in only one patient known to harbor the tumor mutation. CONCLUSIONS: This first-in-human proof-of-concept study shows MRgFUS enriches the signal of circulating brain-derived biomarkers, demonstrating the potential of the technology to support liquid biopsy for the brain.

Quality of life in patients with neurofibromatosis type 1 and 2 in Canada.

BACKGROUND: There is scarce data on the quality of life of people with neurofibromatosis type 1 (NF1) and type 2 (NF2) in Canada. METHODS: A cross-sectional study of adults with NF1 and NF2 attending a tertiary center. Patients completed generic measures (SF-36, EQ-5D-5L, and PROMIS pain interference) and disease-specific questionnaires (PedsQL NF1 module and the NFTI-QOL for NF2). We compared generic scores between NF1 and NF2 individuals and used regression models to assess factors associated with quality of life. RESULTS: Hundred and eighty-four participants were enrolled. Mean age was 33 years in NF1 and 40 years in NF2. NF1 and NF2 individuals had lower employment rates and lower scores in all domains of the SF-36 compared to the general Canadian population (P < .005). Using the EQ-5D-5L, there was a high proportion of pain (64% in NF1 and 74% in NF2) and anxiety/depression (60% in NF1 and 68% in NF2). Pain interference correlated with poor quality of life in NF1 and NF2; perceived physical appearance was the main predictor of mental well-being in NF1. CONCLUSIONS: Individuals with NF1 and NF2 have low quality of life, and this correlates with pain, anxiety, and depression, which are prevalent in NF1 and NF2. Perceived physical appearance predicts quality of life in NF1. A multidisciplinary approach is necessary for patients with NF1 and NF2, including mental health and pain management.

Programmed death ligand-1 (PD-L1) expression in meningioma; prognostic significance and its association with hypoxia and NFKB2 expression.

Management of clinically aggressive meningiomas is a considerable challenge. PD-L1 induced immune suppression has increasingly gained attention in clinical management of cancer; however, to date, the clinical significance and regulatory mechanisms of PD-L1 in meningioma is not yet fully characterized. We sought to characterize PD-L1 expression in meningioma and elucidate its regulatory mechanisms. Immunohistochemical staining of PD-L1 expression in meningiomas showed 43% positivity in both tumor and immune cells and we observed intra and inter tumoral heterogeneity. Univariate and multivariate analyses confirmed that PD-L1 protein expression is an independent prognostic marker for worse recurrence free survival in meningioma. Furthermore, our transcriptomic analysis revealed a strong association between PD-L1 expression and that of NFKB2 and carbonic anhydrase 9 (CA9). We also demonstrated that both of these markers, when co-expressed with PD-L1, predict tumor progression. Our studies on several meningioma cell lines cultured in hypoxic conditions validated the association of CA9 and PD-L1 expression. Here we show the clinical significance of PD-L1 in meningioma as a marker that can predict tumor recurrence. We also show an association PD-L1 expression with NFKB2 expression and its induction under hypoxic conditions. These findings may open new avenues of molecular investigation in pathogenesis of meningioma.

How to live with a meningioma: experiences, symptoms, and challenges reported by patients.

BACKGROUND: We aimed to explore gaps in the care of meningioma patients that could improve quality of care by better understanding symptoms experienced by patients at various stages of treatment, and afterwards. METHODS: A novel 19-item self-administered questionnaire was provided for patients with meningiomas to complete by the American Brain Tumor Association (ABTA) over a 3-month period. RESULTS: A total of 1852 unique respondents were included. Nearly one-third of all respondents felt they received insufficient information about meningiomas at initial diagnosis (N = 607, 32.9%) and 28.8% (N = 530) believed they received insufficient information about treatment options. In fact, 34.5% of respondents received the majority of their information from the internet and nonhealthcare professionals. The most common concerns after initial diagnosis were risks associated with surgery and/or treatment (36.5%) followed by how the tumor would impact daily life (25%) and the risk of tumor recurrence (12.4%). Respondents indicated that a list of resources available for patients with meningiomas (N = 597, 32.3%) would have been most beneficial in regards to their disease experience after their initial diagnosis. Moreover, we found that a substantial proportion of patients continued to report symptoms long after treatment, with fatigue being the most common compared to before treatment (38.2% vs. 57.7%, χ 2 = 128, P < .001). CONCLUSIONS: Patients with meningiomas exhibit symptoms that continue well after treatment with fatigue and cognitive impairments as the most bothersome. Moreover, patients report key communication gaps that can be addressed to improve their disease experience and care.

Cost-effectiveness analysis of MR-guided focused ultrasound thalamotomy for tremor-dominant Parkinson's disease.

OBJECTIVE: The development of transcranial MR-guided focused ultrasound (MRgFUS) has revitalized the practice of lesioning procedures in functional neurosurgery. Previous health economic analysis found MRgFUS thalamotomy to be a cost-effective treatment for patients with essential tremor, supporting its reimbursement. With the publication of level I evidence in support of MRgFUS thalamotomy for patients with tremor-dominant Parkinson's disease (TDPD), the authors performed a health economic comparison between MRgFUS, deep brain stimulation (DBS), and medical therapy. METHODS: The authors used a decision tree model with rollback analysis and one-factor sensitivity analysis. Literature searches of MRgFUS thalamotomy and unilateral DBS of the ventrointermediate nucleus of the thalamus for TDPD were performed to determine the utility and probabilities for the model. Costs in Canadian dollars (CAD) were derived from the Schedule of Benefits and Fees in Ontario, Canada, and expert opinion on usage. RESULTS: MRgFUS was associated with an expected cost of $14,831 CAD. Adding MRgFUS to continued medical therapy resulted in an incremental cost-effectiveness ratio of $30,078 per quality-adjusted life year (QALY), which remained cost-effective under various scenarios in the sensitivity analysis. Comparing DBS to MRgFUS, while DBS did not achieve the willingness-to-pay threshold ($56,503 per QALY) in the base case scenario, it did so under several scenarios in the sensitivity analysis. CONCLUSIONS: MRgFUS thalamotomy is a cost-effective treatment for patients with TDPD, particularly over continued medical therapy. While MRgFUS remains competitive with DBS, the cost-effectiveness advantage is less substantial. These results will help inform the integration of this technology in the healthcare system.

Molecular and Clinical Insights into the Invasive Capacity of Glioblastoma Cells.

The invasive capacity of GBM is one of the key tumoral features associated with treatment resistance, recurrence, and poor overall survival. The molecular machinery underlying GBM invasiveness comprises an intricate network of signaling pathways and interactions with the extracellular matrix and host cells. Among them, PI3k/Akt, Wnt, Hedgehog, and NFkB play a crucial role in the cellular processes related to invasion. A better understanding of these pathways could potentially help in developing new therapeutic approaches with better outcomes. Nevertheless, despite significant advances made over the last decade on these molecular and cellular mechanisms, they have not been translated into the clinical practice. Moreover, targeting the infiltrative tumor and its significance regarding outcome is still a major clinical challenge. For instance, the pre- and intraoperative methods used to identify the infiltrative tumor are limited when trying to accurately define the tumor boundaries and the burden of tumor cells in the infiltrated parenchyma. Besides, the impact of treating the infiltrative tumor remains unclear. Here we aim to highlight the molecular and clinical hallmarks of invasion in GBM.

The central nervous system tumor methylation classifier changes neuro-oncology practice for challenging brain tumor diagnoses and directly impacts patient care.

BACKGROUND: Molecular signatures are being increasingly incorporated into cancer classification systems. DNA methylation-based central nervous system (CNS) tumor classification is being recognized as having the potential to aid in cases of difficult histopathological diagnoses. Here, we present our institutional clinical experience in integrating a DNA-methylation-based classifier into clinical practice and report its impact on CNS tumor patient diagnosis and treatment. METHODS: Prospective case review was undertaken at CNS tumor board discussions over a 3-year period and 55 tumors with a diagnosis that was not certain to two senior neuropathologists were recommended for methylation profiling based on diagnostic needs. Tumor classification, calibrated scores, and copy number variant (CNV) plots were obtained for all 55 cases. These results were integrated with histopathological findings to reach a final diagnosis. We retrospectively reviewed each patient's clinical course to determine final neuro-pathology diagnoses and the impact of methylation profiling on their clinical management, with a focus on changes that were made to treatment decisions. RESULTS: Following methylation profiling, 46 of the 55 (84%) challenging cases received a clinically relevant diagnostic alteration, with two-thirds having a change in the histopathological diagnosis and the other one-third obtaining clinically important molecular diagnostic or subtyping alterations. WHO grading changed by 27% with two-thirds receiving a higher grade. Patient care was directly changed in 15% of all cases with major changes in clinical decision-making being made for these patients to avoid unnecessary or insufficient treatment. CONCLUSIONS: The integration of methylation-based CNS tumor classification into diagnostics has a substantial clinical benefit for patients with challenging CNS tumors while also avoiding unnecessary health care costs. The clinical impact shown here may prompt the expanded use of DNA methylation profiling for CNS tumor diagnostics within prominent neuro-oncology centers globally.

Safety and efficacy of focused ultrasound induced blood-brain barrier opening, an integrative review of animal and human studies.

The blood-brain barrier, while fundamental in maintaining homeostasis in the central nervous system, is a bottleneck to achieving efficacy for numerous therapeutics. Improved brain penetration is also desirable for reduced dose, cost, and systemic side effects. Transient disruption of the blood-brain barrier with focused ultrasound (FUS) can facilitate drug delivery noninvasively with precise spatial and temporal specificity. FUS technology is transcranial and effective without further drug modifications, key advantages that will accelerate adoption and translation of existing therapeutic pipelines. In this review, we performed a comprehensive literature search to build a database and provide a synthesis of ultrasound parameters and drug characteristics that influence the safety and efficacy profile of FUS to enhance drug delivery.