Publications by authors named "Randy Van Ommeren"

We identify a population of Protogenin-positive (PRTG) MYC NESTIN stem cells in the four-week-old human embryonic hindbrain that subsequently localizes to the ventricular zone of the rhombic lip (RL). Oncogenic transformation of early Prtg rhombic lip stem cells initiates group 3 medulloblastoma (Gr3-MB)-like tumors. PRTG stem cells grow adjacent to a human-specific interposed vascular plexus in the RL, a phenotype that is recapitulated in Gr3-MB but not in other types of medulloblastoma.

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Diffuse intrinsic pontine glioma (DIPG) is a lethal pediatric brain tumor and the leading cause of brain tumor-related death in children. As several clinical trials over the past few decades have led to no significant improvements in outcome, the current standard of care remains fractionated focal radiation. Due to the recent increase in stereotactic biopsies, tumor tissue availabilities have enabled our advancement of the genomic and molecular characterization of this lethal cancer.

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Posterior fossa A (PFA) ependymomas are lethal malignancies of the hindbrain in infants and toddlers. Lacking highly recurrent somatic mutations, PFA ependymomas are proposed to be epigenetically driven tumors for which model systems are lacking. Here we demonstrate that PFA ependymomas are maintained under hypoxia, associated with restricted availability of specific metabolites to diminish histone methylation, and increase histone demethylation and acetylation at histone 3 lysine 27 (H3K27).

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Recurrent medulloblastoma and ependymoma are universally lethal, with no approved targeted therapies and few candidates presently under clinical evaluation. Nearly all recurrent medulloblastomas and posterior fossa group A (PFA) ependymomas are located adjacent to and bathed by the cerebrospinal fluid, presenting an opportunity for locoregional therapy, bypassing the blood-brain barrier. We identify three cell-surface targets, EPHA2, HER2 and interleukin 13 receptor α2, expressed on medulloblastomas and ependymomas, but not expressed in the normal developing brain.

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Medulloblastoma (MB) is the most common primary malignant brain tumor of childhood and a significant contributor to pediatric morbidity and death. While metastatic dissemination is the predominant cause of morbidity and mortality for patients with this disease, most research efforts and clinical trials to date have focused on the primary tumor; this is due mostly to the paucity of metastatic tumor samples and lack of robust mouse models of MB dissemination. Most current insights into the molecular drivers of metastasis have been derived from comparative molecular studies of metastatic and non-metastatic primary tumors.

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Advancements in computer vision and artificial intelligence (AI) carry the potential to make significant contributions to health care, particularly in diagnostic specialties such as radiology and pathology. The impact of these technologies on physician stakeholders is the subject of significant speculation. There is however a dearth of information regarding the opinions, enthusiasm, and concerns of the pathology community at large.

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Chronic traumatic encephalopathy (CTE) has become a topic of considerable interest in recent years, with wide-ranging implications for athletes, military members, and other groups exposed to frequent concussive or subconcussive head trauma. The condition has been subject to intensive neuropathological characterization by various groups, with assessment methodologies and staging criteria proposed. Clinical characterization of symptoms has also been performed, but has not yet been definitively formalized.

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The precision-based revolution in medicine continues to demand stratification of patients into smaller and more personalized subgroups. While genomic technologies have largely led this movement, diagnostic results can take days to weeks to generate. Management at, or closer to, the point of care still heavily relies on the subjective qualitative interpretation of clinical and diagnostic imaging findings.

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Lethal neonatal rigidity and multifocal seizure syndrome (RMFSL) (OMIM#614498) is caused by homozygous or compound heterozygous mutation in the BRAT1 gene (OMIM#614506) on chromosome 7p22. We report a newborn female infant born to non-consanguineous Chinese parents who presented with hypertonia, dysmorphic features, progressive encephalopathy with refractory seizures, and worsening episodic apnea, leading to intubation and eventually death at 10 weeks of age. Whole exome sequencing revealed homozygous BRAT1 mutation, c.

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Glioblastoma (GBM) is the most common and malignant primary brain tumor in adults. There is a critical need for novel strategies to abolish the molecular mechanisms that support GBM growth, invasion and treatment resistance. The heat shock proteins, HSP27 and HSP90, serve these pivotal roles in tumor cells and have been identified as effective targets for developing therapeutics.

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The generation of xenograft models, which support the growth of human tissue in animals, forms an important part of a researcher's tool kit and enhances the ability to understand the initiation and development of cancer in vivo. Especially in the context of the brain tumor-initiating cell (BTIC), a xenograft model allows for careful characterization of BTIC roles in tumor initiation, growth, and relapse. Here, we detail a set of procedures which describe the isolation, enrichment, and intracranial injection of human BTICs from patient samples to generate xenograft models of a human brain tumor.

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