Publications by authors named "Geurts M"

Introduction: The optimal treatment for recurrent glioblastoma patients remains not well-defined in international guidelines. On top of that, the availability of national guidelines is uncharted.

Research Question: This study aimed to investigate the availability of national guidelines on the diagnosis and treatment of adult glioma throughout Europe, specifically focusing on recurrent glioblastoma.

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Article Synopsis
  • The mammalian pancreas has three key parts: exocrine acini and ducts, along with endocrine islets, all originating from a common progenitor during development.
  • Researchers created 18 human fetal pancreas organoid lines from samples between 8-17 weeks of gestation, with four lines showing the ability to produce all three cell types while thriving in culture for over two years.
  • Single-cell RNA sequencing revealed LGR5 cells as crucial developmental stem cells, indicating that these organoids are capable of long-term growth and can differentiate into acinar, ductal, and endocrine cells.
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Carcinogenesis results from the sequential acquisition of oncogenic mutations that convert normal cells into invasive, metastasizing cancer cells. Colorectal cancer exemplifies this process through its well-described adenoma-carcinoma sequence, modeled previously using clustered regularly interspaced short palindromic repeats (CRISPR) to induce four consecutive mutations in wild-type human gut organoids. Here, we demonstrate that long-term culture of mismatch-repair-deficient organoids allows the selection of spontaneous oncogenic mutations through the sequential withdrawal of Wnt agonists, epidermal growth factor (EGF) agonists and the bone morphogenetic protein (BMP) antagonist Noggin, while TP53 mutations were selected through the addition of Nutlin-3.

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Enteroendocrine cells (EECs) are gut epithelial cells that respond to intestinal contents by secreting hormones, including the incretins glucagon-like peptide 1 (GLP-1) and gastric inhibitory protein (GIP), which regulate multiple physiological processes. Hormone release is controlled through metabolite-sensing proteins. Low expression, interspecies differences, and the existence of multiple EEC subtypes have posed challenges to the study of these sensors.

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The standard of care for adult patients with gliomas, glioneuronal and neuronal tumors consists of combinations of surgery, radiotherapy, and chemotherapy. For many systemic cancers, targeted treatments are a major part of the standard treatment, however, the predictive significance of most of the targets for treatment in systemic cancer are less well established in central nervous system (CNS) tumors . In 2023 the EANO Guideline Committee presented evidence based recommendations for rational testing of molecular targets for targeted treatments.

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Article Synopsis
  • Patients with brain tumors want to help doctors understand their illness better by participating in tests that involve taking samples of their tumor tissue.
  • To improve treatments, everyone including patients, researchers, and regulatory agencies need to work together and use consistent methods when taking these samples.
  • Even though new tests using blood samples show some promise, they can't replace the need for the usual tissue tests just yet, and it's important to clearly explain the risks and benefits of these procedures to patients.
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In mice, intestinal tuft cells have been described as a long-lived, postmitotic cell type. Two distinct subsets have been identified: tuft-1 and tuft-2 (ref. ).

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For glioblastoma patients, the efficacy-targeted therapy is limited to date. Most of the molecular therapies previously studied are lacking efficacy in this population. More trials are needed to study the actual actionability of biomarkers in (recurrent) glioblastoma.

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Isogenic disease models, such as genetically engineered organoids, provide insight into the impact of genetic variants on organ function. Here, we present a protocol to create isogenic disease models from adult stem cell-derived organoids using next-generation CRISPR tools. We describe steps for single guide RNA (sgRNA) design and cloning, electroporation, and selecting electroporated cells.

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Low-grade gliomas present a formidable challenge in neuro-oncology because of the challenges imposed by the blood-brain barrier, predilection for the young adult population, and propensity for recurrence. In the past two decades, the systematic examination of genomic alterations in adults and children with primary brain tumors has uncovered profound new insights into the pathogenesis of these tumors, resulting in more accurate tumor classification and prognostication. It also identified several common recurrent genomic alterations that now define specific brain tumor subtypes and have provided a new opportunity for molecularly targeted therapeutic intervention.

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We describe a 46-year-old patient with an IDH-wildtype diffusely infiltrating atypical teratoid/rhabdoid tumour (AT/RT), SHH-1B molecular subtype. The unusual histology and subsequent diagnosis in an adult patient will be discussed.

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Article Synopsis
  • FBXW7 is a protein that helps break down other proteins, and when it's mutated, it can contribute to cancer.
  • Scientists used a special tool called CRISPR to change certain parts of this protein in colon tissue samples, which made the samples grow better without needing as much EGF, a growth factor.
  • The research showed that these mutations help keep another protein called EGFR alive longer, making the cancer cells less sensitive to certain treatments.
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Background: The proportion of women among healthcare and biomedical research professionals in neuro-oncology is growing. With changes in cultural expectations and work-life balance considerations, more men aspire to nonfull-time jobs, yet, leadership positions remain dominated by men.

Methods: The European Association of Neuro-Oncology (EANO) disparity committee carried out a digital survey to explore gender balance and actions suitable to promote gender equality.

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H3 K27M-mutant diffuse glioma is a recently identified brain tumor associated with poor prognosis. As of 2016, it is classified by the World Health Organization as a distinct form of grade IV glioma. Despite recognition as an important prognostic and diagnostic feature in diffuse glioma, radiation remains the sole standard of care and no effective systemic therapies are available for H3K27M mutant tumors.

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Cryo-electron microscopy (cryo-EM) enables the determination of membrane protein structures in native-like environments. Characterising how membrane proteins interact with the surrounding membrane lipid environment is assisted by resolution of lipid-like densities visible in cryo-EM maps. Nevertheless, establishing the molecular identity of putative lipid and/or detergent densities remains challenging.

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The most frequent adult-type primary CNS tumours are diffuse gliomas, but a large variety of rarer CNS tumour types exists. The classification of these tumours is increasingly based on molecular diagnostics, which is reflected in the extensive molecular foundation of the recent WHO 2021 classification of CNS tumours. Resection as extensive as is safely possible is the cornerstone of treatment in most gliomas, and is now also recommended early in the treatment of patients with radiological evidence of histologically low-grade tumours.

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Article Synopsis
  • - The study explores the use of advanced CRISPR/Cas9-based base editors for creating intricate tumor models using human organoids derived from adult stem cells (ASC), specifically focusing on liver (hepatocyte) and endometrial organoids.
  • - Results demonstrate the effectiveness of cytosine and adenine base editors in inducing specific mutations, such as CTNNB1 mutations in liver organoids and PTEN nonsense mutations in endometrial organoids, which lead to tumor development even with one mutated copy.
  • - Additionally, the researchers enhanced base editing capabilities by employing multiple Cas9 variants for targeted mutations and established a method to model colorectal cancer by editing five cancer genes simultaneously in one experiment.
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SARS-CoV-2 can enter cells after its spike protein is cleaved by either type II transmembrane serine proteases (TTSPs), like TMPRSS2, or cathepsins. It is now widely accepted that the Omicron variant uses TMPRSS2 less efficiently and instead enters cells via cathepsins, but these findings have yet to be verified in more relevant cell models. Although we could confirm efficient cathepsin-mediated entry for Omicron in a monkey kidney cell line, experiments with protease inhibitors showed that Omicron (BA.

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The age estimation of biological traces is one of the holy grails in forensic investigations. We developed a method for the age estimation of semen stains using fluorescence spectroscopy in conjunction with a stoichiometric ageing model. The model describes the degradation and generation rate of proteins and fluorescent oxidation products (FOX) over time.

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