Both YAP1-MAML2 and constitutively active YAP1 drive the formation of tumors that resemble NF2 mutant meningiomas in mice.

YAP1 is a transcriptional coactivator regulated by the Hippo signaling pathway, including NF2. Meningiomas are the most common primary brain tumors; a large percentage exhibit heterozygous loss of chromosome 22 (harboring the NF2 gene) and functional inactivation of the remaining NF2 copy, implicating oncogenic YAP activity in these tumors. Recently, fusions between YAP1 and MAML2 have been identified in a subset of pediatric NF2 wild-type meningiomas. Here, we show that human YAP1-MAML2-positive meningiomas resemble NF2 mutant meningiomas by global and YAP-related gene expression signatures. We then show that expression of YAP1-MAML2 in mice induces tumors that resemble human YAP1 fusion-positive and NF2 mutant meningiomas by gene expression. We demonstrate that YAP1-MAML2 primarily functions by exerting TEAD-dependent YAP activity that is resistant to Hippo signaling. Treatment with YAP-TEAD inhibitors is sufficient to inhibit the viability of YAP1-MAML2-driven mouse tumors ex vivo. Finally, we show that expression of constitutively active YAP1 (S127/397A-YAP1) is sufficient to induce similar tumors, suggesting that the YAP component of the gene fusion is the critical driver of these tumors. In summary, our results implicate YAP1-MAML2 as a causal oncogenic driver and highlight TEAD-dependent YAP activity as an oncogenic driver in YAP1-MAML2 fusion meningioma as well as NF2 mutant meningioma in general.

Modeling YAP fusions: a paradigm for investigating rare cancers?

Loss of the NF2 tumor suppressor gene is a common finding in meningiomas, and more recently YAP1 fusions have been found in a subset of pediatric NF2 wild-type meningiomas. In the previous issue of Genes & Development, Szulzewsky and colleagues (pp. 857-870) showed that TEAD-dependent YAP1 activity by either the loss of the NF2 gene or YAP1-MAML2 fusion is an oncogenic process promoting meningioma tumorigenesis. Furthermore, pharmacological inhibition of YAP1-TEAD resulted in antitumor activity in both YAP1 fusion-positive and NF2 mutant meningiomas. Together, these data indicate that disruption of the YAP1-TEAD interaction raises a potential therapeutic option for these tumors that requires future investigation.

Intrinsically disordered Meningioma-1 stabilizes the BAF complex to cause AML.

Meningioma-1 (MN1) overexpression in AML is associated with poor prognosis, and forced expression of MN1 induces leukemia in mice. We sought to determine how MN1 causes AML. We found that overexpression of MN1 can be induced by translocations that result in hijacking of a downstream enhancer. Structure predictions revealed that the entire MN1 coding frame is disordered. We identified the myeloid progenitor-specific BAF complex as the key interaction partner of MN1. MN1 over-stabilizes BAF on enhancer chromatin, a function directly linked to the presence of a long polyQ-stretch within MN1. BAF over-stabilization at binding sites of transcription factors regulating a hematopoietic stem/progenitor program prevents the developmentally appropriate decommissioning of these enhancers and results in impaired myeloid differentiation and leukemia. Beyond AML, our data detail how the overexpression of a polyQ protein, in the absence of any coding sequence mutation, can be sufficient to cause malignant transformation.

Pleiotropic role of TRAF7 in skull-base meningiomas and congenital heart disease.

While somatic variants of TRAF7 (Tumor necrosis factor receptor-associated factor 7) underlie anterior skull-base meningiomas, here we report the inherited mutations of TRAF7 that cause congenital heart defects. We show that TRAF7 mutants operate in a dominant manner, inhibiting protein function via heterodimerization with wild-type protein. Further, the shared genetics of the two disparate pathologies can be traced to the common origin of forebrain meninges and cardiac outflow tract from the TRAF7-expressing neural crest. Somatic and inherited mutations disrupt TRAF7-IFT57 interactions leading to cilia degradation. TRAF7-mutant meningioma primary cultures lack cilia, and TRAF7 knockdown causes cardiac, craniofacial, and ciliary defects in Xenopus and zebrafish, suggesting a mechanistic convergence for TRAF7-driven meningiomas and developmental heart defects.

NF2 regulates IP3R-mediated Ca2+ signal and apoptosis in meningiomas.

Meningiomas are the most common primary intracranial tumors and account for nearly 30% of all nervous system tumors. Approximately half of meningioma patients exhibit neurofibromin 2 (NF2) gene inactivation. Here, NF2 was shown to interact with the endoplasmic reticulum (ER) calcium (Ca2+) channel inositol 1,4,5-trisphosphate receptor 1 (IP3R1) in IOMM-Lee, a high-grade malignant meningioma cell line, and the F1 subdomain of NF2 plays a critical role in this interaction. Functional assays indicated that NF2 promotes the phosphorylation of IP3R (Ser 1756) and IP3R-mediated endoplasmic reticulum (ER) Ca2+ release by binding to IP3R1, which results in Ca2+-dependent apoptosis. Knockout of NF2 decreased Ca2+ release and promoted resistance to apoptosis, which was rescued by wild-type NF2 overexpression but not by F1 subdomain deletion truncation overexpression. The effects of NF2 defects on the development of tumors were further studied in mouse models. The decreased expression level of NF2 caused by NF2 gene knockout or mutation affects the activity of the IP3R channel, which reduces Ca2+-dependent apoptosis, thereby promoting the development of tumors. We elucidated the interaction patterns of NF2 and IP3R1, revealed the molecular mechanism through which NF2 regulates IP3R1-mediated Ca2+ release, and elucidated the new pathogenic mechanism of meningioma-related NF2 variants. Our study broadens the current understanding of the biological function of NF2 and provides ideas for drug screening of NF2-associated meningioma.

Related mechanisms, current treatments, and new perspectives in meningioma.

Meningiomas are non-glial tumors that are the most common primary brain tumors in adults. Although meningioma can possibly be cured with surgical excision, variations in atypical/anaplastic meningioma have a high recurrence rate and a poor prognosis. As a result, it is critical to develop novel therapeutic options for high-grade meningiomas. This review highlights the current histology of meningiomas, prevalent genetic and molecular changes, and the most extensively researched signaling pathways and therapies in meningiomas. It also reviews current clinical studies and novel meningioma treatments, including immunotherapy, microRNAs, cancer stem cell methods, and targeted interventions within the glycolysis pathway. Through the examination of the complex landscape of meningioma biology and the highlighting of promising therapeutic pathways, this review opens the way for future research efforts aimed at improving patient outcomes in this prevalent intracranial tumor entity.

α-Mannosylated HLA-II glycopeptide antigens dominate the immunopeptidome of immortalised cells and tumour tissues.

Immunopeptides are cell surface-located protein fragments that aid our immune system to recognise and respond to pathogenic insult and malignant transformation. In this two-part communication, we firstly summarise and reflect on our recent discovery documenting that MHC-II-bound immunopeptides from immortalised cell lines prevalently carry N-glycans that differ from the cellular glycoproteome (Goodson, Front Immunol, 2023), data discussed at the 2023 SfG Annual Meeting. These findings are important as immunopeptide glycosylation remains poorly understood in immunosurveillance. The study also opened up new technical and biological questions that we address in the second part of this communication. Our study highlighted that the performance of the search engines used to detect glycosylated immunopeptides from LC-MS/MS data remains untested and, importantly, that little biochemical in vivo evidence is available to document the nature of glycopeptide antigens in tumour tissues. To this end, we compared the N-glycosylated MHC-II-bound immunopeptides that were reported from tumour tissues of 14 meningioma patients in the MSFragger-HLA-Glyco database (Bedran, Nat Commun, 2023) to those we identified with the commercial Byonic software. Encouragingly, the search engines produced similar outputs supporting that N-glycosylated MHC-II-bound immunopeptides are prevalent in meningioma tumour tissues. Consistent also with in vitro findings, the tissue MHC-II-bound immunopeptides were found to predominantly carry hyper-processed (paucimannosidic- and chitobiose core-type) and hypo-processed (oligomannosidic-type) N-glycans that varied in prevalence and distribution between patients. Taken together, evidence is emerging suggesting that α-mannosidic glycoepitopes abundantly decorate MHC-II-bound immunopeptides in both immortalised cells and tumour tissues warranting further research into their functional roles in immunosurveillance.

Computer-Aided Multiphoton Microscopy Diagnosis of 5 Different Primary Architecture Subtypes of Meningiomas.

Meningiomas rank among the most common intracranial tumors, and surgery stands as the primary treatment modality for meningiomas. The precise subtyping and diagnosis of meningiomas, both before and during surgery, play a pivotal role in enabling neurosurgeons choose the optimal surgical program. In this study, we utilized multiphoton microscopy (MPM) based on 2-photon excited fluorescence and second-harmonic generation to identify 5 common meningioma subtypes. The morphological features of these subtypes were depicted using the MPM multichannel mode. Additionally, we developed 2 distinct programs to quantify collagen content and blood vessel density. Furthermore, the lambda mode of the MPM characterized architectural and spectral features, from which 3 quantitative indicators were extracted. Moreover, we employed machine learning to differentiate meningioma subtypes automatically, achieving high classification accuracy. These findings demonstrate the potential of MPM as a noninvasive diagnostic tool for meningioma subtyping and diagnosis, offering improved accuracy and resolution compared with traditional methods.

Cognitive brain activity before and after surgery in meningioma patients.

Neuropsychological studies have demonstrated that meningioma patients frequently exhibit cognitive deficits before surgery and show only limited improvement after surgery. Combining neuropsychological with functional imaging measurements can shed more light on the impact of surgery on cognitive brain function. We aimed to evaluate whether surgery affects cognitive brain activity in such a manner that it may mask possible changes in cognitive functioning measured by neuropsychological tests. Twenty-three meningioma patients participated in a fMRI measurement using a verbal working memory task as well as three neuropsychological tests focused on working memory, just before and 3 months after surgery. A region of interest based fMRI analysis was used to examine cognitive brain activity at these timepoints within the central executive network and default mode network. Neuropsychological assessment showed impaired cognitive functioning before as well as 3 months after surgery. Neuropsychological test scores, in-scanner task performance as well as brain activity within the central executive and default mode network were not significantly different between both timepoints. Our results indicate that surgery does not significantly affect cognitive brain activity in meningioma patients the first few months after surgery. Therefore, the lack of cognitive improvement after surgery is not likely the result of compensatory processes in the brain. Cognitive deficits that are already present before surgery appear to be persistent after surgery and a considerable recovery period. Our study shows potential leads that comprehensive cognitive evaluation can be of added value so that cognitive functioning may become a more prominent factor in clinical decision making.

Immune cell infiltration and inflammatory landscape in primary brain tumours.

BACKGROUND: Primary malignant brain tumours are more than one-third of all brain tumours and despite the molecular investigation to identify cancer driver mutations, the current therapeutic options available are challenging due to high intratumour heterogeneity. In addition, an immunosuppressive and inflammatory tumour microenvironment strengthens cancer progression. Therefore, we defined an immune and inflammatory profiling of meningioma and glial tumours to elucidate the role of the immune infiltration in these cancer types. METHODS: Using tissue microarrays of 158 brain tumour samples, we assessed CD3, CD4, CD8, CD20, CD138, Granzyme B (GzmB), 5-Lipoxygenase (5-LOX), Programmed Death-Ligand 1 (PD-L1), O-6-Methylguanine-DNA Methyltransferase (MGMT) and Transglutaminase 2 (TG2) expression by immunohistochemistry (IHC). IHC results were correlated using a Spearman correlation matrix. Transcript expression, correlation, and overall survival (OS) analyses were evaluated using public datasets available on GEPIA2 in Glioblastoma (GBM) and Lower Grade Glioma (LGG) cohorts. RESULTS: Seven out of ten markers showed a significantly different IHC expression in at least one of the evaluated cohorts whereas CD3, CD4 and 5-LOX were differentially expressed between GBMs and astrocytomas. Correlation matrix analysis revealed that 5-LOX and GzmB expression were associated in both meningiomas and GBMs, whereas 5-LOX expression was significantly and positively correlated to TG2 in both meningioma and astrocytoma cohorts. These findings were confirmed with the correlation analysis of TCGA-GBM and LGG datasets. Profiling of mRNA levels indicated a significant increase in CD3 (CD3D, CD3E), and CD138 (SDC1) expression in GBM compared to control tissues. CD4 and 5-LOX (ALOX5) mRNA levels were significantly more expressed in tumour samples than in normal tissues in both GBM and LGG. In GBM cohort, GzmB (GZMB), SDC1 and MGMT gene expression predicted a poor overall survival (OS). Moreover, in LGG cohort, an increased expression of CD3 (CD3D, CD3E, CD3G), CD8 (CD8A), GZMB, CD20 (MS4A1), SDC1, PD-L1, ALOX5, and TG2 (TGM2) genes was associated with worse OS. CONCLUSIONS: Our data have revealed that there is a positive and significant correlation between the expression of 5-LOX and GzmB, both at RNA and protein level. Further evaluation is needed to understand the interplay of 5-LOX and immune infiltration in glioma progression.

A gain of function mutation in AKT1 increases hexokinase 2 and diminishes oxidative stress in meningioma.

Increasing evidence suggests the oncogenic role of missense mutation (AKT1-E17K) of AKT1 gene in meningiomas. Upon investigating the connection between the pro-tumorigenic role of AKT1-E17K and cellular metabolic adaptations, elevated levels of glycolytic enzyme hexokinase 2 (HK2) was observed in meningioma patients with AKT1-E17K compared to patients harboring wild-type AKT1. In vitro experiments also suggested higher HK2 levels and its activity in AKT1-E17K cells. Treatment with the conventional drug of choice AZD5363 (a pan AKT inhibitor) enhanced cell death and diminished HK2 levels in AKT1 mutants. Given the role of AKT phosphorylation in eliciting inflammatory responses, we observed increased levels of inflammatory mediators (IL-1ß, IL6, IL8, and TLR4) in AKT1-E17K cells compared to AKT1-WT cells. Treatment with AKT or HK2 inhibitors dampened the heightened levels of inflammatory markers in AKT1-E17K cells. As AKT and HK2 regulates redox homeostasis, diminished ROS generation concomitant with increased levels of NF-E2- related factor 2 (Nrf2) and superoxide dismutase 1 (SOD1) were observed in AKT1-E17K cells. Increased sensitivity of AKT1-E17K cells to AZD5363 in the presence of HK2 inhibitor Lonidamine was reversed upon treatment with ROS inhibitor NAC. By affecting metabolism, inflammation, and redox homeostasis AKT1-E17K confers a survival advantage in meningioma cells. Our findings suggest that targeting AKT-HK2 cross-talk to induce ROS-dependent cell death could be exploited as novel therapeutic approach in meningiomas.

Regression of all untreated lesions in multifocal low-grade meningioma following fractionated stereotactic radiotherapy-abscopal effect or spontaneous regression? : Case report and review of the literature.

PURPOSE: Abscopal effects have been reported predominantly in metastatic cancers, indicating a radiographic response in a lesion that has not been included in the radiotherapy target volume. The response is interpreted as a humoral immune response to radiotherapy-generated tumour-specific antigens. In this case study, we present the first histologically confirmed multifocal low-grade meningioma with spontaneous regression of all other lesions after conventionally fractionated stereotactic radiotherapy (RT). CASE REPORT: Two localisations, right frontal and right spheno-orbital, were resected at the time of the initial diagnosis in a 66-year-old woman. RT was performed 1 year later to a progressive occipital lesion at the cerebral falx. RESULTS: Regular magnetic resonance imaging (MRI) showed slightly decreasing tumour volume in untreated lesions 1 year after RT and continued during further follow-up. Up to > 7 years after treatment, MRI demonstrated an almost complete response of all initial lesions. Two prior reports with meningioma were published in one patient with an atypical meningioma after conventionally fractionated RT and another patient with an intracranial meningiomatosis after radiosurgery. CONCLUSION: This case study supports the concepts of treating only progressive or symptomatic meningioma lesions locally and careful regular MRI surveillance for further assessment. Potential active interventions to trigger an abscopal effect are currently not known. Further research of this beneficial effect for our patients should be supported.

Quality requirements for MRI simulation in cranial stereotactic radiotherapy: a guideline from the German Taskforce "Imaging in Stereotactic Radiotherapy".

Accurate Magnetic Resonance Imaging (MRI) simulation is fundamental for high-precision stereotactic radiosurgery and fractionated stereotactic radiotherapy, collectively referred to as stereotactic radiotherapy (SRT), to deliver doses of high biological effectiveness to well-defined cranial targets. Multiple MRI hardware related factors as well as scanner configuration and sequence protocol parameters can affect the imaging accuracy and need to be optimized for the special purpose of radiotherapy treatment planning. MRI simulation for SRT is possible for different organizational environments including patient referral for imaging as well as dedicated MRI simulation in the radiotherapy department but require radiotherapy-optimized MRI protocols and defined quality standards to ensure geometrically accurate images that form an impeccable foundation for treatment planning. For this guideline, an interdisciplinary panel including experts from the working group for radiosurgery and stereotactic radiotherapy of the German Society for Radiation Oncology (DEGRO), the working group for physics and technology in stereotactic radiotherapy of the German Society for Medical Physics (DGMP), the German Society of Neurosurgery (DGNC), the German Society of Neuroradiology (DGNR) and the German Chapter of the International Society for Magnetic Resonance in Medicine (DS-ISMRM) have defined minimum MRI quality requirements as well as advanced MRI simulation options for cranial SRT.

Establishment of tumor microenvironment-preserving organoid model from patients with intracranial meningioma.

BACKGROUND: Although meningioma is the most common primary brain tumor, treatments rely on surgery and radiotherapy, and recurrent meningiomas have no standard therapeutic options due to a lack of clinically relevant research models. Current meningioma cell lines or organoids cannot reflect biological features of patient tumors since they undergo transformation along culture and consist of only tumor cells without microenvironment. We aim to establish patient-derived meningioma organoids (MNOs) preserving diverse cell types representative of the tumor microenvironment. METHODS: The biological features of MNOs were evaluated using WST, LDH, and collagen-based 3D invasion assays. Cellular identities in MNOs were confirmed by immunohistochemistry (IHC). Genetic alteration profiles of MNOs and their corresponding parental tumors were obtained by whole-exome sequencing. RESULTS: MNOs were established from four patients with meningioma (two grade 1 and two grade 2) at a 100% succession rate. Exclusion of enzymatic dissociation-reaggregation steps endowed MNOs with original histology and tumor microenvironment. In addition, we used a liquid media culture system instead of embedding samples into Matrigel, resulting in an easy-to-handle, cost-efficient, and time-saving system. MNOs maintained their functionality and morphology after long-term culture (> 9 wk) and repeated cryopreserving-recovery cycles. The similarities between MNOs and their corresponding parental tumors were confirmed by both IHC and whole-exome sequencing. As a representative application, we utilized MNOs in drug screening, and mifepristone, an antagonist of progesterone receptor, showed prominent antitumor efficacy with respect to viability, invasiveness, and protein expression. CONCLUSION: Taken together, our MNO model overcame limitations of previous meningioma models and showed superior resemblance to parental tumors. Thus, our model could facilitate translational research identifying and selecting drugs for meningioma in the era of precision medicine.

Joint EANM/EANO/RANO/SNMMI practice guideline/procedure standards for diagnostics and therapy (theranostics) of meningiomas using radiolabeled somatostatin receptor ligands: version 1.0.

PURPOSE: To provide practice guideline/procedure standards for diagnostics and therapy (theranostics) of meningiomas using radiolabeled somatostatin receptor (SSTR) ligands. METHODS: This joint practice guideline/procedure standard was collaboratively developed by the European Association of Nuclear Medicine (EANM), the Society of Nuclear Medicine and Molecular Imaging (SNMMI), the European Association of Neurooncology (EANO), and the PET task force of the Response Assessment in Neurooncology Working Group (PET/RANO). RESULTS: Positron emission tomography (PET) using somatostatin receptor (SSTR) ligands can detect meningioma tissue with high sensitivity and specificity and may provide clinically relevant information beyond that obtained from structural magnetic resonance imaging (MRI) or computed tomography (CT) imaging alone. SSTR-directed PET imaging can be particularly useful for differential diagnosis, delineation of meningioma extent, detection of osseous involvement, and the differentiation between posttherapeutic scar tissue and tumour recurrence. Moreover, SSTR-peptide receptor radionuclide therapy (PRRT) is an emerging investigational treatment approach for meningioma. CONCLUSION: These practice guidelines will define procedure standards for the application of PET imaging in patients with meningiomas and related SSTR-targeted PRRTs in routine practice and clinical trials and will help to harmonize data acquisition and interpretation across centers, facilitate comparability of studies, and to collect larger databases. The current document provides additional information to the evidence-based recommendations from the PET/RANO Working Group regarding the utilization of PET imaging in meningiomas Galldiks (Neuro Oncol. 2017;19(12):1576-87). The information provided should be considered in the context of local conditions and regulations.

Chronic hyperglycemia and intracranial meningiomas.

Meningiomas are among the most common primary tumors of the central nervous system. Previous research into the meningioma histological appearance, genetic markers, transcriptome and epigenetic landscape has revealed that benign meningiomas significantly differ in their glucose metabolism compared to aggressive lesions. However, a correlation between the systemic glucose metabolism and the metabolism of the tumor hasn't yet been found. We hypothesized that chronic levels of glycaemia (approximated with glycated hemoglobin (HbA1c)) are different in patients with aggressive and benign meningiomas. The study encompassed 71 patients with de novo intracranial meningiomas, operated on in three European hospitals, two in Croatia and one in Spain. Our results show that patients with WHO grade 2 meningiomas had significantly higher HbA1c values compared to patients with grade 1 lesions (P = 0.0290). We also found a significant number of patients (19/71; 26.7%) being hyperglycemic, harboring all the risks that such a condition entails. Finally, we found a significant correlation between our patients' age and their preoperative HbA1c levels (P = 0.0008, ρ(rho) = 0.388), suggesting that older meningioma patients are at a higher risk of having their glycaemia severely dysregulated. These findings are especially important considering the current routine and wide-spread use of corticosteroids as anti-edematous treatment. Further research in this area could lead to better understanding of meningiomas and have immediate clinical impact.

Plasma extracellular vesicles in meningioma patients following radiotherapy as liquid biopsy- a prospective explorative biomarker study (ARO 2023-05/AG-NRO-07).

BACKGROUND: While surgical resection remains the primary treatment approach for symptomatic or growing meningiomas, radiotherapy represents an auspicious alternative in patients with meningiomas not safely amenable to surgery. Biopsies are often omitted in light of potential postoperative neurological deficits, resulting in a lack of histological grading and (molecular) risk stratification. In this prospective explorative biomarker study, extracellular vesicles in the bloodstream will be investigated in patients with macroscopic meningiomas to identify a biomarker for molecular risk stratification and disease monitoring. METHODS: In total, 60 patients with meningiomas and an indication of radiotherapy (RT) and macroscopic tumor on the planning MRI will be enrolled. Blood samples will be obtained before the start, during, and after radiotherapy, as well as during clinical follow-up every 6 months. Extracellular vesicles will be isolated from the blood samples, quantified and correlated with the clinical treatment response or progression. Further, nanopore sequencing-based DNA methylation profiles of plasma EV-DNA will be generated for methylation-based meningioma classification. DISCUSSION: This study will explore the dynamic of plasma EVs in meningioma patients under/after radiotherapy, with the objective of identifying potential biomarkers of (early) tumor progression. DNA methylation profiling of plasma EVs in meningioma patients may enable molecular risk stratification, facilitating a molecularly-guided target volume delineation and adjusted dose prescription during RT treatment planning.

Epidemiology, characteristics, and prognostic factors of lymphoplasmacyte-rich meningioma: a systematic literature review.

BACKGROUNDS: Lymphoplasmacyte-rich meningioma(LPM) is a rare subtype of meningioma with a low degree of malignancy and an overall preferable prognosis. The purpose of this article is to increase the understanding of the disease, reduce misdiagnosis, and improve prognosis. METHODS: A search was conducted in the PubMed database for English articles published from 1993 to 2023. The keywords were "lymphoplasmacyte-rich (all fields) and meningioma (all fields) and English (lang)" and "lymphoplasmacyte-rich meningioma (title/abstract) and English (lang)".We further analyzed the clinical manifestations, imaging manifestations, pathological features, treatment strategies, and prognosis of LPM.The possible prognostic indicators were analyzed by the log-rank test and Pearson's chi-squared test. RESULTS: Fourteen reports with 95 LPM patients were included in this report, including 47 males and 48 females who were diagnosed between the ages of 9 and 79, with an average age of 45 years. The most common clinical manifestations are headache and limb movement disorders. In most cases, the tumor occurred on the convex portion of the brain. All tumors showed significant enhancement, with homogeneous enhancement being more common, and most patients showed peritumoral edema. Postoperative pathological EMA, LCA, and vimentin positivity were helpful for the final diagnosis of the patient. Log-rank tests showed a correlation between complete resection and better prognosis and recurrence. CONCLUSION: There is a lack of significant differences in the clinical symptoms and imaging manifestations of LPM compared to other diseases that need to be differentiated, and a clear diagnosis requires pathological examination. After standardized surgical treatment, the recurrence rate and mortality rate of LPM are both low. Complete surgical resection of tumors is associated with a better prognosis and lower recurrence rate.

Hsa_circ_0004872 alleviates meningioma progression by sponging miR-190a-3p/PTEN signaling.

BACKGROUND: Meningioma, the most prevalent intracranial tumor, possesses a significant propensity for malignant transformation. Circular RNAs (circ-RNAs), a class of non-coding RNAs, have emerged as crucial players in tumorigenesis. This study explores the functional relevance of hsa_circ_0004872, a specific circ-RNA, in the context of meningioma. METHODS: Molecular structure and stability of hsa_circ_0004872 were elucidated through PCR identification. Meningioma cell proliferation and apoptosis were assessed using the CCK-8 assay and flow cytometry, respectively. Gene and protein expression were analyzed via qRT-PCR and western blot. Molecular interactions were confirmed through dual-luciferase reporter gene and RIP assays. RESULTS: Hsa_circ_0004872, derived from exons 2 to 4 of the host gene MAPK1, demonstrated enhanced stability compared to its host MAPK1. Clinical data described that hsa_circ_0004872 was reduced in meningioma tissues and cell lines, and negatively correlated to poor survival rate of meningioma patients. Overexpression of hsa_circ_0004872 exhibited inhibitory effects on cell proliferation and promotion of apoptosis in vitro. Subsequent investigations unveiled a direct interaction between hsa_circ_0004872 and miR-190a-3p, leading to the activation of the PI3K/AKT signaling pathway through targeting PTEN. Notably, miR-190a-3p silence accelerated the apoptosis and proliferation inhibition of meningioma cells by inactivating PTEN/PI3K/AKT signaling, while miR-190a-3p overexpression showed an opposite effect, which greatly reversed the anti-tumor effects of hsa_circ_0004872 overexpression. CONCLUSION: In summary, our findings highlighted the intricate role of hsa_circ_0004872 in meningioma, shedding light on the regulatory mechanisms involving circ-RNAs in tumor progression. This positions hsa_circ_0004872 as a potential key regulatory factor in meningioma with implications for future therapeutic interventions.

Preoperative Subtyping of WHO Grade 1 Meningiomas Using a Single-Shot Ultrafast MR T2 Mapping.

BACKGROUND: Meningioma subtype is crucial in treatment planning and prognosis delineation, for grade 1 meningiomas. T2 relaxometry could provide detailed microscopic information but is often limited by long scanning times. PURPOSE: To investigate the potential of T2 maps derived from multiple overlapping-echo detachment imaging (MOLED) for predicting meningioma subtypes and Ki-67 index, and to compare the diagnostic efficiency of two different region-of-interest (ROI) placements (whole-tumor and contrast-enhanced, respectively). STUDY TYPE: Prospective. PHANTOM/SUBJECTS: A phantom containing 11 tubes of MnCl2 at different concentrations, eight healthy volunteers, and 75 patients with grade 1 meningioma. FIELD STRENGTH/SEQUENCE: 3 T scanner. MOLED, T2-weighted spin-echo sequence, T2-dark-fluid sequence, and postcontrast T1-weighted gradient echo sequence. ASSESSMENT: Two ROIs were delineated: the whole-tumor area (ROI1) and contrast-enhanced area (ROI2). Histogram parameters were extracted from T2 maps. Meningioma subtypes and Ki-67 index were reviewed by a neuropathologist according to the 2021 classification criteria. STATISTICAL TESTS: Linear regression, Bland-Altman analysis, Pearson's correlation analysis, independent t test, Mann-Whitney U test, Kruskal-Wallis test with Bonferroni correction, and multivariate logistic regression analysis with the P-value significance level of 0.05. RESULTS: The MOLED T2 sequence demonstrated excellent accuracy for phantoms and volunteers (Meandiff = -1.29%, SDdiff = 1.25% and Meandiff = 0.36%, SDdiff = 2.70%, respectively), and good repeatability for volunteers (average coefficient of variance = 1.13%; intraclass correlation coefficient = 0.877). For both ROI1 and ROI2, T2 variance had the highest area under the curves (area under the ROC curve = 0.768 and 0.761, respectively) for meningioma subtyping. There was no significant difference between the two ROIs (P = 0.875). Significant correlations were observed between T2 parameters and Ki-67 index (r = 0.237-0.374). DATA CONCLUSION: MOLED T2 maps can effectively differentiate between meningothelial, fibrous, and transitional meningiomas. Moreover, T2 histogram parameters were significantly correlated with the Ki-67 index. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 2.