Publications by authors named "Josef Vormoor"

Background: With many rare tumour types, acquiring the correct diagnosis is a challenging but crucial process in paediatric oncology. Historically, this is done based on histology and morphology of the disease. However, advances in genome wide profiling techniques such as RNA sequencing now allow the development of molecular classification tools.

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We profiled a large heterogenous cohort of matched diagnostic-relapse tumour tissue and paired plasma-derived cell free DNA (cfDNA) from patients with relapsed and progressive solid tumours of childhood. Tissue and cfDNA sequencing results were concordant, with a wider spectrum of mutant alleles and higher degree of intra-tumour heterogeneity captured by the latter, if sufficient circulating tumour-derived DNA (ctDNA) was present. Serial tumour sequencing identified putative drivers of relapse, with alterations in epigenetic drivers being a common feature.

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Background: It is well documented that traditional health care models do not meet the specific needs of Adolescents and Young Adults (AYA) cancer patients.

Methods: We explore a map of the development of age-specific AYA cancer care across Europe, from the perspective of healthcare professionals with an interest in AYA care, in order to understand the specific challenges and map progress over time. An on-line survey was developed by international professional cancer organisations.

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Sarcopenia in pediatric hemato-oncology patients is undesirable because of the consequences it may have for treatment continuation and outcome, physical abilities and participation in daily life. An easy-to-use screening tool for sarcopenia will facilitate the identification of children at risk who need interventions to prevent serious physical deterioration. In the elderly, the use of the SARC-F score as a case-finding tool for sarcopenia is recommended.

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iTHER is a Dutch prospective national precision oncology program aiming to define tumour molecular profiles in children and adolescents with primary very high-risk, relapsed, or refractory paediatric tumours. Between April 2017 and April 2021, 302 samples from 253 patients were included. Comprehensive molecular profiling including low-coverage whole genome sequencing (lcWGS), whole exome sequencing (WES), RNA sequencing (RNA-seq), Affymetrix, and/or 850k methylation profiling was successfully performed for 226 samples with at least 20% tumour content.

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Leukemia cells re-program their microenvironment to augment blast proliferation and enhance treatment resistance. Means of clinically targeting such niche-driven treatment resistance remain ambiguous. We develop human induced pluripotent stem cell (hiPSC)-engineered niches to reveal druggable cancer-niche dependencies.

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Article Synopsis
  • The MLL/AF4 fusion gene is linked to a high-risk form of pro-B acute lymphoblastic leukemia, where relapses may switch the cancer type to acute myeloid leukemia, complicating treatment.
  • Research shows that during these relapses, the cancer cells retain specific genetic characteristics from the original leukemia and can develop from different stages of cell development.
  • Changes in chromatin accessibility and gene regulation, particularly involving the CHD4 gene, contribute to this lineage switching, suggesting that the cancer's development is driven by faulty epigenetic control.
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Rarely, immunophenotypically immature B-cell precursor acute lymphoblastic leukemia (BCP-ALL) carries an immunoglobulin- MYC rearrangement (IG-MYC-r). This can result in diagnostic confusion with Burkitt lymphoma/leukemia and use of individualized treatment schedules of unproven efficacy. Here we compare the molecular characteristics of these conditions and investigate historic clinical outcome data.

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Article Synopsis
  • * The study aims to identify the recommended dose of selumetinib while evaluating its effectiveness in reducing leukaemia symptoms, enrolling a total of 26 to 42 patients across multiple countries.
  • * Ethical approval has been obtained from medical committees in participating countries to ensure the study adheres to ethical standards.
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The addition of fludarabine to cyclophosphamide as a lymphodepleting regimen prior to CD19 chimeric antigen receptor (CAR) T-cell therapy significantly improved outcomes in patients with relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (B-ALL). Fludarabine exposure, previously shown to be highly variable when dosing is based on body surface area (BSA), is a predictor for survival in allogeneic hematopoietic cell transplantation (allo-HCT). Hence, we hypothesized that an optimal exposure of fludarabine might be of clinical importance in CD19 CAR T-cell treatment.

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Despite improved outcomes achieved in the last decades for children with newly diagnosed leukaemia and lymphoma, treatment of patients with refractory/relapsed disease remains a challenge. The cure rate is still unsatisfactory and often achieved at the cost of significant morbidity. Exploring treatment with novel agents should offer less toxic therapeutic options, without compromising efficacy.

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(Patho-)physiological activation of the IL7-receptor (IL7R) signaling contributes to steroid resistance in pediatric T-cell acute lymphoblastic leukemia (T-ALL). Here, we show that activating IL7R pathway mutations and physiological IL7R signaling activate MAPK-ERK signaling, which provokes steroid resistance by phosphorylation of BIM. By mass spectrometry, we demonstrate that phosphorylated BIM is impaired in binding to BCL2, BCLXL and MCL1, shifting the apoptotic balance toward survival.

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Article Synopsis
  • - T-cell Acute Lymphoblastic Leukemia (T-ALL) often shows resistance to glucocorticoids, which negatively affects patient outcomes and creates a need for new treatments.
  • - Researchers discovered that the kinase LCK plays an essential role in T-ALL cell proliferation, with LCK inhibition leading to cell cycle arrest and enhanced cell death when combined with the glucocorticoid dexamethasone.
  • - A murine trial demonstrated that the combination therapy significantly reduced the growth of T-ALL cells, suggesting potential improvements for treatment strategies in high-risk T-ALL patients.
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Background: Farber disease (FD) is a rare, lysosomal storage disorder caused by deficient acid ceramidase activity. FD has long been considered a fatal disorder with death in the first three decades of life resulting either from respiratory insufficiency as a consequence of airway involvement or from progressive neurodegeneration because of nervous system involvement. Peripheral symptoms associated with FD, including inflammatory joint disease, have been described to improve relatively rapidly after hematopoietic cell transplantation (HCT).

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Article Synopsis
  • * Combining selumetinib with the steroid dexamethasone enhances cell death through the proapoptotic protein BIM, demonstrating strong synergism in preclinical models.
  • * Ongoing research, including the Seludex trial, is evaluating this combination in children with hard-to-treat acute lymphoblastic leukemia, showing promising results in reducing leukemia burden in mice.
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  • Oncogenic transcription factors like RUNX1/ETO are key drivers of acute myeloid leukemia (AML), presenting unique challenges for therapy.
  • An RNAi screen revealed that Cyclin D2 (CCND2) is vital for the survival and growth of leukemia cells driven by RUNX1/ETO, as it works with AP-1 to boost CCND2 expression.
  • Targeting CCND2 through knockdown or existing drugs hampers the growth of leukemia cells and their ability to thrive in a living organism, suggesting that targeting G1 CCND-CDK complexes could be an effective treatment strategy for AML related to RUNX1/ETO.
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Venetoclax is a highly selective, potent BCL-2 inhibitor that is approved for some patients previously treated for chronic lymphocytic leukemia, and has shown promising activity in adult studies across several hematologic malignancies. Preclinical studies have demonstrated venetoclax activity in pediatric patient-derived xenograft models and cell lines; however, clinical studies in pediatric patients have yet to be conducted. The prognosis is poor for children with most relapsed/refractory malignancies, and limited treatment options result in unmet clinical need.

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New drugs are crucially needed for children with cancer. The European Paediatric Regulation facilitates paediatric class waivers for drugs developed for diseases only occurring in adults. In this Review, we retrospectively searched oncology drugs that were class waivered between June, 2012, and June, 2015.

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In the past decade, the landscape of drug development in oncology has evolved dramatically; however, this paradigm shift remains to be adopted in early phase clinical trial designs for studies of molecularly targeted agents and immunotherapeutic agents in paediatric malignancies. In drug development, prioritization of drugs on the basis of knowledge of tumour biology, molecular 'drivers' of disease and a drug's mechanism of action, and therapeutic unmet needs are key elements; these aspects are relevant to early phase paediatric trials, in which molecular profiling is strongly encouraged. Herein, we describe the strategy of the Innovative Therapies for Children with Cancer (ITCC) Consortium, which advocates for the adoption of trial designs that enable uninterrupted patient recruitment, the extrapolation from studies in adults when possible, and the inclusion of expansion cohorts.

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Aims: AT9283 is used to treat patients with solid tumours and patients with leukaemia. However, the maximum tolerated dose (MTD) for children with leukaemia remains unknown due to early termination of the Phase I trial. The aim of this study was to develop a population model of AT9283 to describe the pharmacokinetics in adults and children and to estimate the MTD in children with leukaemia.

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