DNA methylation-array interlaboratory comparison trial demonstrates highly reproducible paediatric CNS tumour classification across 13 international centres.

Aims: DNA methylation profiling, recently endorsed by the World Health Organisation (WHO) as a pivotal diagnostic tool for brain tumours, most commonly relies on bead arrays. Despite its widespread use, limited data exist on the technical reproducibility and potential cross-institutional differences. The LOGGIC Core BioClinical Data Bank registry conducted a prospective laboratory comparison trial with 12 international laboratories to enhance diagnostic accuracy for paediatric low-grade gliomas, focusing on technical aspects of DNA methylation data generation and profile interpretation under clinical real-time conditions.

Impact of JQ1 treatment on seizures, hippocampal gene expression, and gliosis in a mouse model of temporal lobe epilepsy.

Epilepsy is a neurological disease characterised by recurrent seizures with complex aetiology. Temporal lobe epilepsy, the most common form in adults, can be acquired following brain insults including trauma, stroke, infection or sustained status epilepticus. The mechanisms that give rise to the formation and maintenance of hyperexcitable networks following acquired insults remain unknown, yet an extensive body of literature points towards persistent gene and epigenomic dysregulation as a potential mediator of this dysfunction.

RET overexpression leads to increased brain metastatic competency in luminal breast cancer.

Background: Breast cancer brain metastasis is a rising occurrence, necessitating a better understanding of the mechanisms involved for effective management. Breast cancer brain metastases diverge notably from the primary tumor, with gains in kinase and concomitant losses of steroid signaling observed. In this study, we explored the role of the kinase receptor RET in promoting breast cancer brain metastases and provide a rationale for targeting this receptor.

Somatic variants as a cause of drug-resistant epilepsy including mesial temporal lobe epilepsy with hippocampal sclerosis.

Objective: The contribution of somatic variants to epilepsy has recently been demonstrated, particularly in the etiology of malformations of cortical development. The aim of this study was to determine the diagnostic yield of somatic variants in genes that have been previously associated with a somatic or germline epilepsy model, ascertained from resected brain tissue from patients with multidrug-resistant focal epilepsy.

Methods: Forty-two patients were recruited across three categories: (1) malformations of cortical development, (2) mesial temporal lobe epilepsy with hippocampal sclerosis, and (3) nonlesional focal epilepsy.

Immunoproteasome deficiency results in age-dependent development of epilepsy.

The immunoproteasome is a central protease complex required for optimal antigen presentation. Immunoproteasome activity is also associated with facilitating the degradation of misfolded and oxidized proteins, which prevents cellular stress. While extensively studied during diseases with increasing evidence suggesting a role for the immunoproteasome during pathological conditions including neurodegenerative diseases, this enzyme complex is believed to be mainly not expressed in the healthy brain.

A clinically relevant computed tomography (CT) radiomics strategy for intracranial rodent brain tumour monitoring.

Here, we establish a CT-radiomics based method for application in invasive, orthotopic rodent brain tumour models. Twenty four NOD/SCID mice were implanted with U87R-Luc2 GBM cells and longitudinally imaged via contrast enhanced (CE-CT) imaging. Pyradiomics was employed to extract CT-radiomic features from the tumour-implanted hemisphere and non-tumour-implanted hemisphere of acquired CT-scans.

CPEB4-CLOCK crosstalk during temporal lobe epilepsy.

Objective: Posttranscriptional mechanisms are increasingly recognized as important contributors to the formation of hyperexcitable networks in epilepsy. Messenger RNA (mRNA) polyadenylation is a key regulatory mechanism governing protein expression by enhancing mRNA stability and translation. Previous studies have shown large-scale changes in mRNA polyadenylation in the hippocampus of mice during epilepsy development.

Comparative analysis of deeply phenotyped GBM cohorts of 'short-term' and 'long-term' survivors.

Background: Glioblastoma (GBM) is an aggressive brain cancer that typically results in death in the first 15 months after diagnosis. There have been limited advances in finding new treatments for GBM. In this study, we investigated molecular differences between patients with extremely short (≤ 9 months, Short term survivors, STS) and long survival (≥ 36 months, Long term survivors, LTS).

Brain biopsy in neurological disease of unknown etiology: A single-center 12-year retrospective analysis.

There are no international guidelines for brain biopsy in neurological disease of unknown etiology, yet most practicing neurologists will encounter difficult cases in which biopsy is considered. This patient cohort is heterogenous, and it is unclear in which circumstances biopsy is most useful. We performed an audit of brain biopsies reviewed in our neuropathology department from 2010 to 2021.

Establishing a committee for antemortem reviews of suspect Creutzfeldt-Jakob disease cases in Ireland.

Background: Creutzfeldt-Jakob disease (CJD) is a rapidly progressive, neurodegenerative disease. In Ireland, clinical diagnostics and laboratory testing remain the responsibility of the managing clinician and the Neuropathology Department at the Beaumont Hospital, respectively. Centralized review of individual cases is not undertaken.

MicroRNA inhibition using antimiRs in acute human brain tissue sections.

Antisense inhibition of microRNAs is an emerging preclinical approach to pharmacoresistant epilepsy. A leading candidate is an "antimiR" targeting microRNA-134 (ant-134), but testing to date has used rodent models. Here, we develop an antimiR testing platform in human brain tissue sections.

Microvascular stabilization via blood-brain barrier regulation prevents seizure activity.

Blood-brain barrier (BBB) dysfunction is associated with worse epilepsy outcomes however the underlying molecular mechanisms of BBB dysfunction remain to be elucidated. Tight junction proteins are important regulators of BBB integrity and in particular, the tight junction protein claudin-5 is the most enriched in brain endothelial cells and regulates size-selectivity at the BBB. Additionally, disruption of claudin-5 expression has been implicated in numerous disorders including schizophrenia, depression and traumatic brain injury, yet its role in epilepsy has not been fully deciphered.

Dysplastic gangliocytoma of the cerebellum in a cat.

A 2.5-year-old cat presented with progressive ataxia and lethargy. Magnetic resonance imaging (MRI) showed enlargement of the cerebellum and herniation of cerebellar vermis.

Medullary Serotonergic Binding Deficits and Hippocampal Abnormalities in Sudden Infant Death Syndrome: One or Two Entities?

Sudden infant death syndrome (SIDS) is understood as a syndrome that presents with the common phenotype of sudden death but involves heterogenous biological causes. Many pathological findings have been consistently reported in SIDS, notably in areas of the brain known to play a role in autonomic control and arousal. Our laboratory has reported abnormalities in SIDS cases in medullary serotonin (5-HT) receptor and within the dentate gyrus of the hippocampus.

Melanoma brain metastases in Ireland: surgical and systemic considerations.

Background: Cerebral metastases is a common complication in patients with melanoma. There is a paucity of information in the Republic of Ireland regarding the factors associated with melanoma brain metastases (MBM).

Methods: Patients diagnosed with melanoma brain metastases in Ireland were retrospectively identified in Beaumont Hospital between 1999 and 2018.

Multicystic Encephalomalacia: The Neuropathology of Systemic Neonatal Parechovirus Infection.

The Neuropathology of Human Parechovirus (HPeV) is not widely described due to the relatively recent discovery of the virus combined with a limited number of autopsy case reports. We report the case of an infant boy born at 38 weeks who, six days after birth, presented with fever and severe neurological dysfunction. Human Parechovirus Type 3 (HPeV3) RNA was detected in his cerebrospinal fluid (CSF) and blood.

Comparative analysis of the AIB1 interactome in breast cancer reveals MTA2 as a repressive partner which silences E-Cadherin to promote EMT and associates with a pro-metastatic phenotype.

Steroid regulated cancer cells use nuclear receptors and associated regulatory proteins to orchestrate transcriptional networks to drive disease progression. In primary breast cancer, the coactivator AIB1 promotes estrogen receptor (ER) transcriptional activity to enhance cell proliferation. The function of the coactivator in ER metastasis however is not established.

CNS lymphoma, the Irish experience: A retrospective review of neuropathologically confirmed cases over 10 years.

Background: Central nervous system (CNS) lymphoma is rare, representing 2% of all brain tumors. The commonest subtype is diffuse large B-cell lymphoma (DLBCL), with primary T-cell lymphomas (PCNSTL) accounting for ~ 2%.

Objective: To determine the frequency and describe the key features of CNS lymphoma over a 10-year period in an Irish population.

Infant High-Grade Gliomas Comprise Multiple Subgroups Characterized by Novel Targetable Gene Fusions and Favorable Outcomes.

Infant high-grade gliomas appear clinically distinct from their counterparts in older children, indicating that histopathologic grading may not accurately reflect the biology of these tumors. We have collected 241 cases under 4 years of age, and carried out histologic review, methylation profiling, and custom panel, genome, or exome sequencing. After excluding tumors representing other established entities or subgroups, we identified 130 cases to be part of an "intrinsic" spectrum of disease specific to the infant population.

Impact of the 2016 World Health Organization Classification of Tumours of the Central Nervous System: an Irish experience.

The 2016 World Health Organization Classification of Tumours of the Central Nervous System Tumours represents the most significant update to neuro-oncological tumour classification to date, compared with previous updates. This update reflects the substantial advances in molecular and genetic understanding of both adult and childhood brain tumours which have occurred in recent years. These advances have meant that an increasing array of molecular tests are required to definitively classify a tumour, allowing for a more precise integrated pathological diagnosis, but at the expense of a more challenging pathology workup.

Acute multiple sclerosis lesion pathology does not predict subsequent clinical course-a biopsy study.

Background: Knowledge of the clinical outcome in tumefactive demyelination remains limited.

Aims: This study aims to characterise the natural history of biopsy-proven, pathogen-free, cerebral demyelination in an adult Irish population.

Methods: We identified all patients with biopsy-proven demyelination in a single neuropathology centre between 1999 and 2017.

Evaluation of the specificity of the central diagnostic criterion for chronic traumatic encephalopathy.

Introduction: Chronic traumatic encephalopathy (CTE) is a postmortem diagnosis. Consensus postmortem, but not antemortem, diagnostic criteria have been established. A key factor in these criteria is evidence of phosphorylated-tau (p-tau) around sulcal vessels in the cortex.

Correction to: International experience in the development of patient-derived xenograft models of diffuse intrinsic pontine glioma.

There are two errors and one omission in the original article. Author Gottardo's correct name is Nicholas G. Gottardo, author Hulleman's correct affiliation is no.

International experience in the development of patient-derived xenograft models of diffuse intrinsic pontine glioma.

Purpose: Diffuse intrinsic pontine glioma is the most aggressive form of high grade glioma in children with no effective therapies. There have been no improvements in survival in part due poor understanding of underlying biology, and lack of representative in vitro and in vivo models. Recently, it has been found feasible to use both biopsy and autopsy tumors to generate cultures and xenograft models.