Targeting MERTK on tumour cells and macrophages: a potential intervention for sporadic and NF2-related meningioma and schwannoma tumours.

Meningioma and schwannoma are common tumours of the nervous system. They occur sporadically or as part of the hereditary NF2-related schwannomatosis syndrome. There is an unmet need for new effective drug treatments for both tumour types. In this paper, we demonstrate overexpression/activation of TAM (TYRO3/AXL/MERTK) receptors (TAMs) and overexpression/release of ligand GAS6 in patient-derived meningioma tumour cells and tissue. For the first time, we reveal the formation of MERTK/TYRO3 heterocomplexes in meningioma and schwannoma tissue. We demonstrate the dependence of AXL and TYRO3 expression on MERTK in both tumour types, as well as interdependency of MERTK and AXL expression in meningioma. We show that MERTK and AXL contribute to increased proliferation and survival of meningioma and schwannoma cells, which we inhibited in vitro using the MERTK/FLT3 inhibitor UNC2025 and the AXL inhibitor BGB324. UNC2025 was effective in both tumour types with superior efficacy over BGB324. Finally, we found that TAMs are expressed by tumour-associated macrophages in meningioma and schwannoma tumours and that UNC2025 strongly depleted macrophages in both tumour types.

Biomarkers for differentiating grade II meningiomas from grade I: a systematic review.

INTRODUCTION: There are a number of prognostic markers (methylation, CDKN2A/B) described to be useful for the stratification of meningiomas. However, there are currently no clinically validated biomarkers for the preoperative prediction of meningioma grade, which is determined by the histological analysis of tissue obtained from surgery. Accurate preoperative biomarkers would inform the pre-surgical assessment of these tumours, their grade and prognosis and refine the decision-making process for treatment. This review is focused on the more controversial grade II tumours, where debate still surrounds the need for adjuvant therapy, repeat surgery and frequency of follow up. METHODS: We evaluated current literature for potential grade II meningioma clinical biomarkers, focusing on radiological, biochemical (blood assays) and immunohistochemical markers for diagnosis and prognosis, and how they can be used to differentiate them from grade I meningiomas using the post-2016 WHO classification. To do this, we conducted a PUBMED, SCOPUS, OVID SP, SciELO, and INFORMA search using the keywords; 'biomarker', 'diagnosis', 'atypical', 'meningioma', 'prognosis', 'grade I', 'grade 1', 'grade II' and 'grade 2'. RESULTS: We identified 1779 papers, 20 of which were eligible for systematic review according to the defined inclusion and exclusion criteria. From the review, we identified radiological characteristics (irregular tumour shape, tumour growth rate faster than 3cm3/year, high peri-tumoural blood flow), blood markers (low serum TIMP1/2, high serum HER2, high plasma Fibulin-2) and histological markers (low H3K27me3, low SMARCE1, low AKAP12, high ARIDB4) that may aid in differentiating grade II from grade I meningiomas. CONCLUSION: Being able to predict meningioma grade at presentation using the radiological and blood markers described may influence management as the likely grade II tumours will be followed up or treated more aggressively, while the histological markers may prognosticate progression or post-treatment recurrence. This to an extent offers a more personalised treatment approach for patients.

Fibulin-2: A Novel Biomarker for Differentiating Grade II from Grade I Meningiomas.

There is an unmet need for the identification of biomarkers to aid in the diagnosis, clinical management, prognosis and follow-up of meningiomas. There is currently no consensus on the optimum management of WHO grade II meningiomas. In this study, we identified the calcium binding extracellular matrix glycoprotein, Fibulin-2, via mass-spectrometry-based proteomics, assessed its expression in grade I and II meningiomas and explored its potential as a grade II biomarker. A total of 87 grade I and 91 grade II different meningioma cells, tissue and plasma samples were used for the various experimental techniques employed to assess Fibulin-2 expression. The tumours were reviewed and classified according to the 2016 edition of the Classification of the Tumours of the central nervous system (CNS). Mass spectrometry proteomic analysis identified Fibulin-2 as a differentially expressed protein between grade I and II meningioma cell cultures. Fibulin-2 levels were further evaluated in meningioma cells using Western blotting and Real-time Quantitative Polymerase Chain Reaction (RT-qPCR); in meningioma tissues via immunohistochemistry and RT-qPCR; and in plasma via Enzyme-Linked Immunosorbent Assay (ELISA). Proteomic analyses (p < 0.05), Western blotting (p < 0.05) and RT-qPCR (p < 0.01) confirmed significantly higher Fibulin-2 (FBLN2) expression levels in grade II meningiomas compared to grade I. Fibulin-2 blood plasma levels were also significantly higher in grade II meningioma patients compared to grade I patients. This study suggests that elevated Fibulin-2 might be a novel grade II meningioma biomarker, when differentiating them from the grade I tumours. The trend of Fibulin-2 expression observed in plasma may serve as a useful non-invasive biomarker.

Malignant transformation in craniopharyngiomas.

BACKGROUND: Craniopharyngiomas are successfully managed with surgery and/or adjuvant chemoradiotherapy but have been documented to undergo malignant transformation (MT), albeit very rarely, with only 23 reported cases. The exact cause and pathogenesis of this MT are unknown, although the literature has suggested a possible correlation with radiotherapy. OBJECTIVE: To review the reported cases of malignancy, in particular looking at the incidence, tumor characteristics, previous treatment modalities, and median survival. METHODS: We conducted a PUBMED, SCOPUS, OVID SP, and INFORMA search with a combination of key words: craniopharyngioma, malignancy, transformation, neoplasm, radiation therapy, and anaplastic. We identified 23 cases relevant to our study. RESULTS: Median age at the time of diagnosis of malignant craniopharyngiomas was 31 years (range, 10-66 years); 52.6% of the patients were female. Histologically, the most common tumor types were squamous cell carcinoma (80.96%), with adamantinomatous cell type being the most common morphology (89.47%). We found that 21.7% of the cases were diagnosed as malignant craniopharyngioma at first biopsy. Of the rest, the median time from initial benign diagnosis to MT was 8.5 years (range, 3-55 years). Median overall survival after MT was 6 months (range, 2 weeks-5 years). Using the Spearman rank correlation, we found no correlation between the use of radiation therapy (correlation coefficient, -0.25; P < .05) or its dosage (correlation coefficient, -0.26; P < .05) and MT. CONCLUSION: Malignant craniopharyngiomas are rare and are associated with a poor prognosis. MTs occur years after the initial benign craniopharyngioma diagnosis and are associated with multiple benign craniopharyngioma recurrence. Results also show that, contrary to widespread belief, there is a poor correlation between radiotherapy and MT.

Patient and staff satisfaction with 'day of admission' elective surgery.

OBJECTIVES: To evaluate patient and staff satisfaction with day of admission surgery in a neurosurgical unit and its effect on theatre start times. METHODS AND DESIGN: Patients were admitted to a Neurosciences admission lounge (NAL) for neurosurgery on the morning of their operation if deemed appropriate by their neurosurgical consultant. All patients in the NAL were asked to complete patient satisfaction questionnaires. Staff members involved in the care of these patients also completed a satisfaction questionnaire. Theatre start times were compared with those whose patients had been admitted prior to the day of surgery. 378 patients admitted on the day of surgery, 16 doctors (5 anaesthetists, 7 neurosurgeons and 4 neuro high dependency unit, HDU doctors) and 5 nurses. Patients completed an anonymised emotional mapping patient satisfaction questionnaire, and short interviews were carried out with staff members. Theatre start times were obtained retrospectively from the theatre database for lists starting with patients admitted on the day of surgery, and lists starting with patients admitted prior to the day of surgery. RESULTS: 83% of patients felt positive on arrival in the NAL and 88% felt positive on being seen by the doctors and nurses prior to surgery. Overall 79% of patients gave positive responses throughout their patient pathway. 90% of staff were positive about day of admission surgery and all staff members were satisfied that there were no negative effects on surgical outcome. Theatre start time was on average 27 minutes earlier in patients admitted on the day of surgery. CONCLUSIONS: Neurosurgical patients, appropriately selected, can be admitted on the day of surgery with high staff and patient satisfaction and without delaying theatre start times.