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. METHODS: RET expression was characterized in a cohort of patients with primary and brain metastatic tumors. RET functionality was assessed using pharmacological inhibition and gene silencing in patient-derived brain metastatic tumor explants and in vivo models, organoid models, and brain organotypic cultures. RNA sequencing was used to uncover novel brain metastatic relevant RET mechanisms of action. RESULTS: A statistically significant enrichment of RET in brain metastases was observed in estrogen receptor-positive breast cancer, where it played a role in promoting cancer cell adhesion, survival, and outgrowth in the brain. In vivo, RET overexpression enhanced brain metastatic competency in patient-derived models. At a mechanistic level, RET overexpression was found to enhance the activation of gene programs involved in cell adhesion, requiring EGFR cooperation to deliver a pro-brain metastatic phenotype. CONCLUSION: Our results illustrate, for the first time, the role of RET in regulating colonization and outgrowth of breast cancer brain metastasis and provide data to support the use of RET inhibitors in the management strategy for patients with breast cancer brain metastases.

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. Participants were subdivided based on histopathology of the resected brain. Paired blood- and brain-derived DNA samples were sequenced using high-coverage targeted next generation sequencing to high depth (585× and 1360×, respectively). Variants were identified using Genome Analysis ToolKit (GATK4) MuTect-2 and confirmed using high-coverage Amplicon-EZ sequencing. RESULTS: Sequence data on 41 patients passed quality control. Four somatic variants were validated following amplicon sequencing: within CBL, ALG13, MTOR, and FLNA. The diagnostic yield across 41 patients was 10%, 9% in mesial temporal lobe epilepsy with hippocampal sclerosis and 20% in malformations of cortical development. SIGNIFICANCE: This study provides novel insights into the etiology of mesial temporal lobe epilepsy with hippocampal sclerosis, highlighting a potential pathogenic role of somatic variants in CBL and ALG13. We also report candidate diagnostic somatic variants in FLNA in focal cortical dysplasia, while providing further insight into the importance of MTOR and related genes in focal cortical dysplasia. This work demonstrates the potential molecular diagnostic value of variants in both germline and somatic epilepsy genes.

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). METHODS: Patients were selected from an in-house cohort (GLIOTRAIN-cohort), using defined inclusion criteria (Karnofsky score > 70; age < 70 years old; Stupp protocol as first line treatment, IDH wild type), and a multi-omic analysis of LTS and STS GBM samples was performed. RESULTS: Transcriptomic analysis of tumour samples identified cilium gene signatures as enriched in LTS. Moreover, Immunohistochemical analysis confirmed the presence of cilia in the tumours of LTS. Notably, reverse phase protein array analysis (RPPA) demonstrated increased phosphorylated GAB1 (Y627), SRC (Y527), BCL2 (S70) and RAF (S338) protein expression in STS compared to LTS. Next, we identified 25 unique master regulators (MR) and 13 transcription factors (TFs) belonging to ontologies of integrin signalling and cell cycle to be upregulated in STS. CONCLUSION: Overall, comparison of STS and LTS GBM patients, identifies novel biomarkers and potential actionable therapeutic targets for the management of GBM.

Primary CNS EBV-positive post-transplant lymphoproliferative disorder with polymorphic and classic Hodgkin lymphoma features: A case report and literature review.

Post-transplant lymphoproliferative disorders (PTLD) are typically Epstein-Barr virus (EBV)-associated lymphoid or plasmacytic proliferations that occur when immunosuppressed after transplantation. Only 2 cases of primary central nervous system (PCNS) classic Hodgkin lymphoma PTLD and 1 case of PCNS Hodgkin lymphoma-like PTLD have been previously reported. A 59-year-old male presented with malaise, headaches, and dizziness; neuroimaging revealed a 1.7-cm right cerebellar mass and a 0.6-cm right frontal mass. Microscopic examination demonstrated a perivascular and parenchymal polymorphous infiltrate composed of lymphocytes (CD3-positive T cells and CD20-positive B cells), plasma cells, and macrophages. Focally, macrophages had a spindled morphology with a fascicular arrangement amounting to poorly formed granulomata. Mitoses were seen. Scattered large atypical cells were visualized with irregular hyperchromatic nuclei, reminiscent of lacunar cells, mononuclear Hodgkin and binucleate Reed-Sternberg (RS) cells. EBV in situ highlighted a significant number of small lymphoid cells as well as many large atypical forms. Large atypical cells were seen to co-express CD15 and CD30. To our knowledge, this is the first such case with hybrid polymorphic PTLD and classic Hodgkin lymphoma features and the first such case to arise following liver transplantation. This case highlights the histological and immunophenotypic spectrum of these lymphoid proliferations and the resulting challenges in diagnosis and definitive subtyping.

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. Of 9,488 biopsies, 331 biopsies undertaken for an undiagnosed neurological disease were identified. Where documented, the commonest symptoms were hemorrhage, encephalopathy, and dementia. 29% of biopsies were non-diagnostic. The most common clinically relevant findings on biopsy were infection, cerebral amyloid angiopathy with or without angiitis, and demyelination. Rarer conditions included CNS vasculitis, non-infectious encephalitis, and Creutzfeldt Jakob Disease. We highlight the value of brain biopsy in the workup of cryptogenic neurological disease despite recent advances in less invasive diagnostics.

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. AIMS: To determine how diagnostic processes for CJD could be improved in Ireland and to outline the structure and referral process for a new CJD review panel at the Beaumont Hospital. METHODS: We surveyed Irish neurologists' experiences on the management of CJD in Ireland. We measured turnaround times (TAT) for CSF samples referred for diagnostic CJD testing. Finally, we retrospectively reviewed imaging of autopsy-proven CJD cases to compare with initial reports. RESULTS: Ninety-three percent of neurologists supported a national central review of suspect CJD cases. A second clinical opinion was considered to be of likely benefit by 79%. Additionally, 93% reported that a centralized review of neuroradiology would be useful. All respondents felt that expediting turnaround of CSF analysis would be of benefit. The average TAT for CSF testing was 35.4 days. In retrospective review of imaging, all patients demonstrated MRI findings consistent with CJD. However, in only one of these cases were the initial pre-autopsy radiological findings reported as being consistent with CJD. CONCLUSIONS: These findings support the need for improvements to the Irish National CJD Surveillance Unit to maximize antemortem diagnostic accuracy. On foot of this, a clinical CJD Multidisciplinary Team (CJD MDT) has been established to provide a second opinion on (i) the patient's clinical history, (ii) neuroradiology and (iii) and neurophysiology reports (where available).

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. Brain specimens were obtained from patients undergoing resective surgery to treat pharmacoresistant epilepsy. Neocortical specimens were submerged in modified artificial cerebrospinal fluid (ACSF) and dissected for clinical neuropathological examination, and unused material was transferred for sectioning. Individual sections were incubated in oxygenated ACSF, containing either ant-134 or a nontargeting control antimiR, for 24 h at room temperature. RNA integrity was assessed using BioAnalyzer processing, and individual miRNA levels were measured using quantitative reverse transcriptase polymerase chain reaction. Specimens transported in ACSF could be used for neuropathological diagnosis and had good RNA integrity. Ant-134 mediated a dose-dependent knockdown of miR-134, with approximately 75% reduction of miR-134 at 1 µmol L-1 and 90% reduction at 3 µmol L-1 . These doses did not have off-target effects on expression of a selection of three other miRNAs. This is the first demonstration of ant-134 effects in live human brain tissues. The findings lend further support to the preclinical development of a therapy that targets miR-134 and offer a flexible platform for the preclinical testing of antimiRs, and other antisense oligonucleotide therapeutics, in human brain.

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. Patient demographics; age at diagnosis of primary melanoma, age at detection of MBM, year of detection of MBM, anatomical location of primary melanoma, BRAF mutation analysis and the number of metastases were investigated. Follow-up data were also derived, including overall survival. RESULTS: There has being a 158% increase in the incidence of primary melanoma from 1999 compared to 2016. Over the same time period 128 patients with melanoma brain metastases were diagnosed. There was a significant male predominance (n = 77/128; 60%; p < 0.0001). BRAF mutation and leptomeningeal disease were independent prognostic factors in our cohort with a median survival 8 months and 0.5 months, respectively. CONCLUSIONS: Male predominance, leptomeningeal disease and BRAF mutation represent important considerations in this population group. The results of this study add to our knowledge concerning outcomes in melanoma brain metastases and may be useful in clinical planning and future treatments.

A clinical, molecular genetics and pathological study of a FTDP-17 family with a heterozygous splicing variant c.823-10G>T at the intron 9/exon 10 of the MAPT gene.

We report the first clinical-radiological-genetic-molecular-pathological study of a kindred with c.823-10G>T MAPT intronic variant (rs63749974) associated with frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17). We describe the clinical spectrum within this family and emphasize the association between MAPT gene variants and motor neuron disease. This report of a second family with FTDP-17 associated with c.823-10G>T MAPT variant strongly supports pathogenicity of the variant and confirms it is a 4-repeat (4R) tauopathy. This intronic point mutation, probably strengthens the polypyrimidine tract and alters the splicing of exon 10 (10 nucleotides into intron 9) close to the 3' splice site.

Primary intradural/extradural Ewing's sarcoma of the sacral spine: A case report and literature review.

BACKGROUND: Ewing's sarcoma (ES) is a malignant mesenchymal tumor, most often found in the long bones, and usually affecting children and adolescents in the second decade of life. ES of the spine is a clinical rarity. CASE DESCRIPTION: A 45-year-old male presented with a 3-month history of lower back pain which acutely worsened in conjunction with urinary retention. The magnetic resonance imaging revealed a mass extending from L5 to S2 with additional extension through the left S2-3 neural foramen. The metastatic workup was negative. At surgery, the lesion was both intradural and extradural. Following complete surgical resection, the patient was later treated with radiation and chemotherapy. CONCLUSION: Here, we report an adult male who acutely presented with low back pain attributable to primary intradural/extradural sacral ES.

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. Here we describe AIB1 as a survival factor, regulator of pro-metastatic transcriptional pathways and a promising actionable target. Genomic alterations and functional expression of AIB1 associated with reduced disease-free survival in patients and enhanced metastatic capacity in novel CDX and PDX ex-vivo models of ER+ metastatic disease. Comparative analysis of the AIB1 interactome with complementary RNAseq characterized AIB1 as a transcriptional repressor. Specifically, we report that AIB1 interacts with MTA2 to form a repressive complex, inhibiting CDH1 (encoding E-cadherin) to promote EMT and drive progression. We further report that pharmacological and genetic inhibition of AIB1 demonstrates significant anti-proliferative activity in patient-derived models establishing AIB1 as a viable strategy to target endocrine resistant metastasis. This work defines a novel role for AIB1 in the regulation of EMT through transcriptional repression in advanced cancer cells with a considerable implication for prognosis and therapeutic interventions.

A Surviving Case of Acanthamoeba Granulomatous Amebic Encephalitis in a Hematopoietic Stem Cell Transplant Recipient.

BACKGROUND Acanthamoeba are free-living amoebae with potential to infect immunocompromised hosts. The mortality rate of granulomatous amebic encephalitis (GAE) due to Acanthamoeba exceeds 90% and there are currently no reports of survival of this infection in recipients of hematopoietic stem cell transplant. CASE REPORT We report herein the case of a 32-year-old man presenting to our service with abrupt neurological deterioration and seizures 5 months after allogeneic stem cell transplantation for Hodgkin lymphoma. Clinical and imaging findings were non-specific at presentation. Multiple circumscribed, heterogenous, mass-like lesions were identified on MRI. Brain biopsy was performed and revealed multiple cysts and trophozoites suggesting a diagnosis of granulomatous amebic encephalitis. PCR testing confirmed Acanthamoeba. Treatment with miltefosine, metronidazole, azithromycin, fluconazole, pentamidine isethionate, and co-trimoxazole was instituted and the patient survived and shows continued improvement with intensive rehabilitation. CONCLUSIONS We report the first successful outcome in this setting. The diagnosis would have been missed on cerebrospinal fluid analysis alone, but was rapidly made by histological analysis of brain biopsy. This diagnostically challenging infection is likely under-recognized. Early brain biopsy and commencement of a prolonged miltefosine-containing anti-ameba regimen can be curative.

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. MATERIALS AND METHODS: This retrospective review was carried out using the neuropathology database in Beaumont hospital, the largest of two national neurosurgical centers, to identify all cases of CNS lymphoma from 2007 to 2017. Clinical, radiological, morphological, immunophenotype, and molecular information was recorded where available. RESULTS: We identified 149 cases of CNS lymphoma from 2007 to 2017, which equated to a cumulative incidence rate of 0.4/100,000 persons. Median age at diagnosis was 66 years, and 46% were male. 86% were classified as DLBCL (n = 128), 10% immunodeficiency-associated CNS lymphoma (n = 15), 3% PCNSTL (n = 4), and 1% (n = 2) cases of intravascular large B-cell lymphoma. Location in declining frequency was as follows: supratentorial (n = 125), infratentorial (n = 22), spinal (n = 1), and orbital (n = 1). CONCLUSION: This is the first study in an Irish population to determine a cumulative incidence rate of CNS lymphoma, which is in line with larger international population-based registries. No significant trends in incidence rate have been observed from 2007 to 2017. DLBCL is the commonest subtype encountered. Rare variants including PCNSTL can pose a significant diagnostic challenge, and in this setting, molecular studies can be useful to confirm diagnoses.

Angiocentric glioma: Drop Metastases to the Spinal Cord.

BACKGROUND: Angiocentric glioma (AG) is an epileptogenic low grade (World Health Organization grade I) glial tumor with astrocytic and ependymal differentiation, most commonly affecting the pediatric and adolescent population. Despite its infiltrating histological growth kinetics, it is widely accepted that AG has a low potential for aggressive behavior. CASE DESCRIPTION: We present the case of a 42-year-old man who represents the first documented case of not only extracranial manifestation of AG, but also spinal metastatic dissemination. Our patient initially presented with a generalized tonic clonic seizure; following a biopsy, he was diagnosed with a low-grade supratentorial astrocytoma and subsequently received fractionated radiotherapy. He presented 10 months later with worsening dorsal column symptoms and was found to have a contrast-enhancing intradural extramedullary lesion that was surgically resected and histologically confirmed as an AG. CONCLUSION: Further research is required to examine the microenvironment and potential for malignant change in this tumor.

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. We review the changes incorporated into the 2016 classification and describe the impact of these changes in an Irish neuropathology laboratory.

Metastasis of papillary thyroid carcinoma to the thoracic spine.

INTRODUCTION: Papillary thyroid carcinoma (PTC) is the most common form of well-differentiated thyroid carcinoma. Despite its well-differentiated microscopic features, PTC may be minimally or overtly invasive. We present the case of a patient in whom thoracic spinal cord compression was the first presentation of metastatic PTC. CASE REPORT: A 65-year-old woman presented with deteriorating mobility over a 2-month period. Her past history was significant for a right hemithyroidectomy 10 years prior. Examination revealed bilateral lower limb weakness, worse on the right side. Investigations showed a large extradural contrast-enhancing mass at the T7 spinal level. Laminectomy and debulking of this lesion was undertaken. Histopathological examination revealed PTC. The patient proceeded to further treatment with external beam radiotherapy. DISCUSSION: Spinal metastases are an unusual presentation of PTC. Further research into the outcomes for these patients is imperative to bettering our ability to care for these patients through a multi-modality approach.
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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. A baseline, and at least one follow-up MRI scan was available in each instance (mean of 3 scans per patient), together with both the presenting and most recent clinical details including disability level and disease-modifying drugs. RESULTS: In 21 patients, white matter biopsies showed the following: macrophages with myelin debris, myelin-axonal dissociation, reactive astrocytes and occasional lymphocytes. During a mean follow-up time of 8 years (± 4.4), 17 patients developed MS, confirmed both clinically and on MRI, using the 2010 McDonald criteria: 11 relapsing remitting (RR) MS, four secondary progressive and two primary progressive MS. Four patients had a monophasic illness with lesion regression, without clinical or radiological evidence of any further disease activity on follow-up. The patients with progressive MS had significantly higher levels of physical disability than either the RRMS or monophasic patients. CONCLUSION: Uniform white matter subacute demyelination is associated with a diverse clinical course ranging from a monophasic illness to progressive MS, suggesting that extraneous factors distinct from the basic pathology significantly influence the clinical course in MS.

Machine learning: a useful radiological adjunct in determination of a newly diagnosed glioma's grade and IDH status.

INTRODUCTION: Machine learning methods have been introduced as a computer aided diagnostic tool, with applications to glioma characterisation on MRI. Such an algorithmic approach may provide a useful adjunct for a rapid and accurate diagnosis of a glioma. The aim of this study is to devise a machine learning algorithm that may be used by radiologists in routine practice to aid diagnosis of both: WHO grade and IDH mutation status in de novo gliomas. METHODS: To evaluate the status quo, we interrogated the accuracy of neuroradiology reports in relation to WHO grade: grade II 96.49% (95% confidence intervals [CI] 0.88, 0.99); III 36.51% (95% CI 0.24, 0.50); IV 72.9% (95% CI 0.67, 0.78). We derived five MRI parameters from the same diagnostic brain scans, in under two minutes per case, and then supplied these data to a random forest algorithm. RESULTS: Machine learning resulted in a high level of accuracy in prediction of tumour grade: grade II/III; area under the receiver operating characteristic curve (AUC) = 98%, sensitivity = 0.82, specificity = 0.94; grade II/IV; AUC = 100%, sensitivity = 1.0, specificity = 1.0; grade III/IV; AUC = 97%, sensitivity = 0.83, specificity = 0.97. Furthermore, machine learning also facilitated the discrimination of IDH status: AUC of 88%, sensitivity = 0.81, specificity = 0.77. CONCLUSIONS: These data demonstrate the ability of machine learning to accurately classify diffuse gliomas by both WHO grade and IDH status from routine MRI alone-without significant image processing, which may facilitate usage as a diagnostic adjunct in clinical practice.