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  • 1
    In: Neuro-Oncology, Oxford University Press (OUP), Vol. 24, No. Supplement_1 ( 2022-06-03), p. i156-i156
    Abstract: Pediatric central nervous system (CNS) tumors differ substantially from their adult counterparts, are marked by considerable molecular and clinical heterogeneity, and diagnosis through histopathology alone can be challenging. Using DNA methylation-based CNS tumor classification in combination with copy number and RNAseq analysis, we identify a rare, novel pediatric CNS tumor type (n=32) which is characterized by focal high-level amplification and consecutive overexpression of one of the PLAG family genes – PLAGL1 or PLAGL2. It is epigenetically divergent from other known tumor types such as high-grade gliomas, medulloblastomas, embryonal tumors, or CNS sarcomas. The wide range of original histopathologic diagnosis rendered attests to their polyphenotypic nature in terms of morphology. We suggest that these tumors may arise from early to intermediate neural progenitor cells with some neuronal commitment. Using ChIPseq data, we show that both PLAGL1 and PLAGL2 act as transcription factors for: i) the oncogenic kinase RET, a potential drug target, that was overexpressed in our cohort; ii) components of the Wnt/β-Catenin pathway; iii) a set of imprinted genes, reported to regulate the imprinted gene network in mouse models, that was deregulated in the PLAGL-amplified tumors. Consequently, a 250-gene expression PLAGL-signature indicated dysregulation of imprinting control and differentiation/development as a prominent feature. We report differences regarding age and sex distribution between PLAGL1- and PLAGL2-amplified tumors and shed light on differences in clinical behavior and outcomes between these subtypes in male and female patients. PLAGL1-amplified tumors were more prevalent in school-age children and teenagers, while PLAGL2-amplified cases occurred in very young patients. Kaplan-Meier analysis showed a trend towards a more favorable outcome in patients with PLAGL1-amplified tumors and in female patients. Survival rates remained constant after 5 years with a five-/ten-year overall survival of 75% for PLAGL1, 24% for PLAGL2, 18% for male patients, and 88% for female patients.
    Type of Medium: Online Resource
    ISSN: 1522-8517 , 1523-5866
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2022
    detail.hit.zdb_id: 2094060-9
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  • 2
    Online Resource
    Online Resource
    Oxford University Press (OUP) ; 2022
    In:  Neuro-Oncology Vol. 24, No. Supplement_1 ( 2022-06-03), p. i66-i66
    In: Neuro-Oncology, Oxford University Press (OUP), Vol. 24, No. Supplement_1 ( 2022-06-03), p. i66-i66
    Abstract: Gliomas are the most common type of central nervous system (CNS) tumors in children. Therapy and outcome often reflect the grade of the tumor, with high grade glioma (HGG) leading to a significantly worse survival prognosis than low grade glioma. However, HGG are highly diverse regarding their molecular entities and clinical associations. In some pediatric-type histone 3 K27M mutated HGG, the zinc-finger transcription factor PLAG1 was previously found to be overexpressed, which is also confirmed by patient data from the INFORM program. Further, in a novel type of embryonic CNS tumors without histone mutations, the PLAG1-related genes PLAGL1/PLAGL2 are amplified. However, the consequences of aberrant PLAG gene expression on CNS tumor formation during development are unknown. Especially the understanding of downstream signaling pathways that are commonly altered by this transcription factor family could provide necessary starting points for more specific therapy. We use transgenic mouse models with targeted PLAG1 overexpression in neural stem and progenitor cells to investigate the function of PLAG1 in cerebral cortex development and tumorigenesis. We found that PLAG1 overexpression together with heterozygous loss of p53 activity causes neurological defects and impaired cortex development. Next, to understand how PLAG gene overexpression affects neural specification, we will overexpress the PLAG genes in embryonic neural stem and progenitor cells using in utero electroporation. After FACS isolation of electroporated cells and single nucleus RNA sequencing, we will assess how the overexpression changes the transcriptional trajectories of neural development in mouse cortex stem and progenitor cells. We hypothesize that an early event leads to the constitutive upregulation of PLAG genes, which are usually tightly regulated during development, in patients with pediatric brain tumors harboring aberrant PLAG gene expression. Deciphering the transcriptional downstream pathways of this aberrant expression in neural stem and progenitor cells seems promising to find new potential therapeutic targets.
    Type of Medium: Online Resource
    ISSN: 1522-8517 , 1523-5866
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2022
    detail.hit.zdb_id: 2094060-9
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  • 3
    In: Neuro-Oncology, Oxford University Press (OUP), Vol. 25, No. Supplement_1 ( 2023-06-12), p. i39-i40
    Abstract: Pediatric-type gliomas are the most common type of central nervous system tumors in children. They are highly diverse regarding their molecular entities and clinical associations, and they differ from their adult counterparts. A subset of pediatric-type high grade gliomas, including H3K27M mutated diffuse midline glioma, overexpresses the developmentally regulated transcription factor gene PLAG1. Two novel tumor types displaying amplifications or fusions with the related PLAGL1 and PLAGL2 genes have also recently been described (PMIDs 36437415, 34355256). How PLAG-family dysregulation drives tumor formation is currently unknown, however. We generated a novel mouse model that overexpresses hPLAG1 during brain development using a Cre-LoxP approach. Mice that overexpress hPLAG1 together with loss of trp53 in the Nestin-Cre lineage develop brain tumors by 3 months of age with 100 % penetrance. Intriguingly, tumors develop in different brain regions, with hotspots in the thalamus or inferior hypothalamus, the latter likely emerging from the brainstem. All mouse brains contain regions in the brainstem, thalamus and the prefrontal cortex with diffuse patterns of PLAG1+; KI67+ proliferating single cells. Using bulk-RNA sequencing, we identified several genes involved in embryonic brain development, which are still active in the tumors of adult mice. We hypothesize that continued overexpression of PLAG1 locks cells in an aberrant developmental state, making them susceptible for further oncogenic hits and ultimately leading to pediatric glioma formation. We are currently using single-nucleus RNA-seq to determine the developmental trajectories of single tumor cells to identify putative cells-of-origin and primary developmental pathways. Our work will elucidate the consequences of PLAG1 overexpression in pediatric brain tumors and its contribution to tumorigenesis. In the future, we hope to identify genetic dependencies of PLAG1 to generate novel treatment options.
    Type of Medium: Online Resource
    ISSN: 1522-8517 , 1523-5866
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2023
    detail.hit.zdb_id: 2094060-9
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  • 4
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 72, No. 8_Supplement ( 2012-04-15), p. LB-398-LB-398
    Abstract: Background: Head and Neck Squamous Cell Carcinoma (HNSCC) is the 6th most common cancer worldwide. Little is known about changes in copy number (CN) in many cancer associated genes in this tumor type, which may contribute to carcinogenesis and could become useful treatment targets in the future. Many analyses of CN are complicated by the need to use formalin-fixed paraffin-embedded (FFPE) tissues posing technical challenges. We determined copy number alterations (CNA) using a novel, medium-throughput technology (NanoString nCounter) in order to determine common cancer associated CNAs and assess its performance in FFPE tissues. Results were compared with more established technologies such as SNP array, aCGH, and qPCR. Methods: We investigated CNA in 124 tumor specimens and 22 cell lines for 100 literature curated cancer genes using the NanoString nCounter. Most samples were OCT frozen tissues, with a small subset having both OCT frozen, and FFPE tissues. Slides were assessed for tumor content by a HNC pathologist and samples with at least 60% tumor content selected. DNA was extracted using standard column-based methods (Qiagen). We performed CN analysis in 124 frozen (+4 matching FFPE) HNSCC specimens and cell lines (Nanostring nCounter assay) focusing on a selection of cancer associated genes. Furthermore we used aCGH and SNP-CHIP to analyse 20 and 4 cell lines respectively two of which were covered by all three methods. FGFR1 was assessed by qPCR. For FFPE samples a special Nanostring probeset was used with 3-5 probes per gene to provide redundancy with degraded DNA samples. HPV status of samples was assessed by a nested PCR for E6. Results Copy number changes detected by Nanostring and aCGH correlated well. The Nanostring nCounter assay appeared more accurate in calling deletions, which were detected in MST1R, PBRM1, PTPRD for instance. We found amplifications in multiple samples and genes, e.g. CCND1, EGFR, MDM4, MYC, VEGFA, PAX9, ITGB4, SSND1, CTTN, FADD, FGF19, ORAOV1, PPFIA1, some of which were frequently (n & gt;50 samples) or highly amplified ( & gt;30 copies). Some of these amplifications such as ORAOV1 and PPFIA1 seemed higher/more frequent in HPV(-) compared to HPV(+) samples. Samples with FGFR1 amplification were validated using qPCR and correlated very closely. FFPE sample processing was uncomplicated using the FFPE probeset. While some probes failed, using degraded FFPE derived DNA, the redundancy of probes allowed accurate calling of CNA that closely correlated with frozen sample results. Conclusions Copy number alterations are frequent in HNSCC and involve many cancer associated genes, including potentially targetable genes such as EGFR, MDM4, and PIK3CA. Most of the CN changes are recurrent. Amplifications and deletions to some extent differed depending on HPV status. The role and implications of these CN aberrations in a clinical setting need to be further elucidated and validated. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-398. doi:1538-7445.AM2012-LB-398
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2012
    detail.hit.zdb_id: 2036785-5
    detail.hit.zdb_id: 1432-1
    detail.hit.zdb_id: 410466-3
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  • 5
    In: Acta Neuropathologica, Springer Science and Business Media LLC, Vol. 145, No. 4 ( 2023-04), p. 511-514
    Type of Medium: Online Resource
    ISSN: 0001-6322 , 1432-0533
    RVK:
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 1458410-4
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  • 6
    In: Acta Neuropathologica, Springer Science and Business Media LLC, Vol. 145, No. 1 ( 2023-01), p. 49-69
    Abstract: 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. In addition, we report histology, patient characteristics, and survival data in this tumor type. We describe a biologically distinct pediatric CNS tumor type ( n  = 31 cases) that is characterized by focal high-level amplification and resultant overexpression of either PLAGL1 or PLAGL2 , and an absence of recurrent genetic alterations characteristic of other pediatric CNS tumor types. Both genes act as transcription factors for a regulatory subset of imprinted genes (IGs), components of the Wnt/β-Catenin pathway, and the potential drug targets RET and CYP2W1 , which are also specifically overexpressed in this tumor type. A derived PLAGL-specific gene expression signature indicates dysregulation of imprinting control and differentiation/development. These tumors occurred throughout the neuroaxis including the cerebral hemispheres, cerebellum, and brainstem, and were predominantly composed of primitive embryonal-like cells lacking robust expression of markers of glial or neuronal differentiation (e.g., GFAP, OLIG2, and synaptophysin). Tumors with PLAGL1 amplification were typically diagnosed during adolescence (median age 10.5 years), whereas those with PLAGL2 amplification were diagnosed during early childhood (median age 2 years). The 10-year overall survival was 66% for PLAGL1 -amplified tumors, 25% for PLAGL2 -amplified tumors, 18% for male patients, and 82% for female patients. In summary, we describe a new type of biologically distinct CNS tumor characterized by PLAGL1/2 amplification that occurs predominantly in infants and toddlers ( PLAGL2 ) or adolescents ( PLAGL1 ) which we consider best classified as a CNS embryonal tumor and which is associated with intermediate survival. The cell of origin and optimal treatment strategies remain to be defined.
    Type of Medium: Online Resource
    ISSN: 0001-6322 , 1432-0533
    RVK:
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 1458410-4
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