Publications by authors named "David Meyronet"

Background: High-risk medulloblastoma (HRMB) is rare in adults. The 5-year overall survival rate is less than 60%. We present here a retrospective analysis of adults treated with an intensive pediatric chemo-radiotherapy regimen PNET HR + 5: NCT00936156.

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Purpose: Diffuse midline gliomas (DMG) with H3K27 alterations (H3K27M-DMG) are a highly aggressive form of brain cancer. In rare cases, H3K27 mutations have been observed in diffuse non-midline gliomas (DNMG). It is currently unclear how these tumors should be classified.

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Background: Based on preclinical studies showing that IDH-mutant (IDHm) gliomas could be vulnerable to PARP inhibition we launched a multicenter phase 2 study to test the efficacy of olaparib monotherapy in this population.

Methods: Adults with recurrent IDHm high-grade gliomas (HGGs) after radiotherapy and at least one line of alkylating chemotherapy were enrolled. The primary endpoint was a 6-month progression-free survival rate (PFS-6) according to response assessment in neuro-oncology criteria.

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Background: Oncogenic FGFR-TACC fusions are present in 3-5% of high-grade gliomas (HGGs). Fexagratinib (AZD4547) is an oral FGFR1-3 inhibitor with preclinical activity in FGFR-TACC+ gliomas. We tested its safety and efficacy in patients with recurrent FGFR-TACC + HGGs.

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The aim was to identify predictors of progression in a series of patients managed for an intracranial hemangioblastoma, in order to guide the postoperative follow-up modalities. The characteristics of 81 patients managed for an intracranial hemangioblastoma between January 2000 and October 2022 were retrospectively analyzed. The mean age at diagnosis was of 48 ± 16 years.

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Article Synopsis
  • The RESECT study aimed to evaluate the effectiveness of 5-aminolevulinic acid (5-ALA) fluorescence-guided surgery (FGS) compared to conventional white-light microsurgery for glioblastoma resection in a randomized trial across 21 French neurosurgical centers.
  • The study involved 171 patients, with those receiving 5-ALA showing a significantly higher rate of gross-total resection (GTR) at 79.1% compared to 47.8% in the placebo group.
  • Despite differences in surgical success, both groups reported similar postoperative performance scores, indicating that while 5-ALA improved resection rates, it did not significantly affect overall recovery in terms of the Karnof
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Amyloid-β (Aβ) plaques from Alzheimer's Disease (AD) can be visualized ex vivo in label-free brain samples using synchrotron X-ray phase-contrast tomography (XPCT). However, for XPCT to be useful as a screening method for amyloid pathology, it is essential to understand which factors drive the detection of Aβ plaques. The current study was designed to test the hypothesis that Aβ-related contrast in XPCT could be caused by Aβ fibrils and/or by metals trapped in the plaques.

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Background: Median survival with glioblastoma remains in the range of 12 months on population levels. Only few patients survive for more than 5 years. Patient and disease features associated with long-term survival remain poorly defined.

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Background: Pseudoprogression in gliomas has been extensively described after radiotherapy with or without chemotherapy, but not after chemotherapy alone. Here we describe the occurrence of pseudoprogression in patients with anaplastic oligodendrogliomas treated with postoperative procarbazine, lomustine and vincristine (PCV) chemotherapy alone.

Methods: We retrospectively reviewed the medical and radiological files of patients with 1p/19q codeleted, IDH-mutant anaplastic oligodendrogliomas treated with PCV chemotherapy alone who presented magnetic resonance imaging (MRI) modifications suggestive of tumour progression and in whom the final diagnosis was a pseudoprogression.

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Background: APP duplication is a rare genetic cause of Alzheimer disease and cerebral amyloid angiopathy (CAA). We aimed to evaluate the phenotypes of APP duplications carriers.

Methods: Clinical, radiological, and neuropathological features of 43 APP duplication carriers from 24 French families were retrospectively analyzed, and MRI features and cerebrospinal fluid (CSF) biomarkers were compared to 40 APP-negative CAA controls.

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Histopathology is the gold standard for fungal infection (FI) diagnosis, but it does not provide a genus and/or species identification. The objective of the present study was to develop targeted next-generation sequencing (NGS) on formalin-fixed tissue samples (FTs) to achieve a fungal integrated histomolecular diagnosis. Nucleic acid extraction was optimized on a first group of 30 FTs with Aspergillus fumigatus or infection by macrodissecting the microscopically identified fungal-rich area and comparing Qiagen and Promega extraction methods through DNA amplification by A.

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Embryonic stem cell (ESC) fate decisions are regulated by a complex circuitry that coordinates gene expression at multiple levels from chromatin to mRNA processing. Recently, ribosome biogenesis and translation have emerged as key pathways that efficiently control stem cell homeostasis, yet the underlying molecular mechanisms remain largely unknown. Here, we identified RSL24D1 as highly expressed in both mouse and human pluripotent stem cells.

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Background: Gliomas with FGFR3::TACC3 fusion mainly occur in adults, display pathological features of glioblastomas (GB) and are usually classified as glioblastoma, IDH-wildtype. However, cases demonstrating pathological features of low-grade glioma (LGG) lead to difficulties in classification and clinical management. We report a series of 8 GB and 14 LGG with FGFR3:TACC3 fusion in order to better characterize them.

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Microsatellite instability (MSI) is a molecular signature of mismatch repair deficiency (dMMR), a predictive marker of immune checkpoint inhibitor therapy response. Despite its recognized pan-cancer value, most methods only support detection of this signature in colorectal cancer. In addition to the tissue-specific differences that impact the sensitivity of MSI detection in other tissues, the performance of most methods is also affected by patient ethnicity, tumor content, and other sample-specific properties.

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Pediatric central nervous system (CNS) tumors represent the most common cause of cancer-related death in children aged 0-14 years. They differ from their adult counterparts, showing extensive clinical and molecular heterogeneity as well as a challenging histopathological spectrum that often impairs accurate diagnosis. Here, we use DNA methylation-based CNS tumor classification in combination with copy number, RNA-seq, and ChIP-seq analysis to characterize a newly identified CNS tumor type.

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Adult tumors diagnosed as cerebellar glioblastoma (cGBM) are rare and their optimal classification remains to be determined. The aim of this study was to identify subgroups of cGBM based on targeted molecular analysis. cGBM diagnosed between 2003 and 2017 were identified from the French Brain Tumor Database and reviewed according to the WHO 2021 classification.

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Article Synopsis
  • Glioblastoma (GBM) is a very dangerous brain tumor that is hard to treat, even with a lot of research.
  • Scientists are now looking at the area around the tumor (called the tumor microenvironment) to understand how it affects the tumor and how to fight it better.
  • This review brings together ideas from doctors and researchers in France to explain what the tumor microenvironment is like and how it can help create better treatments for GBM.
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The detection of cancer stem-like cells (CSCs) is mainly based on molecular markers or functional tests giving a posteriori results. Therefore label-free and real-time detection of single CSCs remains a difficult challenge. The recent development of microfluidics has made it possible to perform high-throughput single cell imaging under controlled conditions and geometries.

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Article Synopsis
  • A study analyzed the occurrence and characteristics of pseudoprogression in high-grade gliomas with isocitrate dehydrogenase mutations (IDHmt HGG), focusing on patients treated with radiotherapy within the French POLA network.
  • The research found that 19% of patients experienced pseudoprogression, typically developing asymptomatic contrast-enhanced lesions within 2 years post-treatment, with the occurrence linked to the use of certain chemotherapies (PCV CT).
  • The study highlights a concerning trend of misdiagnosis, where 17% of patients with initial true progression may have actually had pseudoprogression, suggesting that careful evaluation is necessary in the early stages post-radiotherapy.
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