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Meningiomas are the most frequent primary brain tumor. Usually, they are curable by surgery, but even after seemingly complete resection, some low-grade lesions recur. Despite recent improvements, signatures having prognostic value in grade I tumors remain poorly characterized. The frequency and delicate location of these tumors suggest that the risk of recurrence might be more accurately predicted. Herein, we show an easy way to evaluate the methylation status of meningiomas and its correlation with the prognosis of the disease. A series of 120 meningiomas, including primary tumors and recurrences, were analyzed histopathologically, and 24 tumor suppressor genes (TSGs) were studied by methylation-specific multiple ligation probe amplification. Long-term follow-up was conducted to classify patients with grade I primary tumors according to their outcomes. We found that hypermethylation in at least one TSG is frequent. The number of hypermethylated TSG per case was significantly higher in recurrences than in primary tumors and in primary benign meningiomas that recurred than in tumors from patients who showed no evidence of disease during follow-up. Finally, hypermethylation in RASSF1A, MLH1, and CDKN2B was an independent prognostic factor associated with the time to recurrence of these benign tumors that were biologically aggressive. To our knowledge, this is one of the widest studies of primary grade I tumors of patients who developed a tumor recurrence. The frequency of epigenetic changes suggests that hypermethylation is an early event in meningiomas, whereas the accumulation of epigenetic changes is related to greater biological aggressiveness and may be a signature of potential clinical relevance., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Meningiomas add up to 25% of intracranial tumors. Although the majority is considered histologically benign, the prediction of their potential aggressiveness is still unclear. We studied the histopathology and aberrations of chromosomes 1p, 14, and 22 by FISH (fluorescence in situ hybridization) in histologically benign meningiomas of 70 patients for the purpose of defining the prognostic value of these alterations in tumoral progression and the risk of recurrence. According to the WHO histopathological criteria, the study set comprised 53 benign, 11 atypical, and 6 anaplastic meningiomas. In benign meningiomas, 25% of the cases displayed a normal karyotype, isolated monosomy 22 (36%), monosomy 22 + 1p deletion (14%), 1p deletion (10%), monosomy 22 + 14q deletion (5%), monosomy 22 + 1p deletion + 14q deletion (5%), or other alterations (5%). Grade II meningiomas presented losses in chromosome 14 in most of the cases (67%), and Grade III meningiomas showed alterations in chromosome 14 in all patients. We observed an overall relapse rate of 31%: recurrence was observed in 19% of Grade I meningiomas, 64% of Grade II, and 83% of Grade III. 9 out of 10 recurrent cases revealed abnormalities in chromosomes 1 and 14, which was a notably higher incidence compared to the series of tumors without relapse. Thus, benign meningiomas with cytogenetic alterations in chromosomes 1p and 14 may be more closely related to atypical meningiomas than benign meningiomas without these alterations, especially in terms of recurrence risk.

Around 20% of meningiomas histologically benign may be clinically aggressive and recur. This strongly affects management of meningioma patients. There is a need to evaluate the potential aggressiveness of an individual meningioma. Additional criteria for better classification of meningiomas will improve clinical decisions as well as patient follow up strategy after surgery. The aim of this study was to determine the relationship between gene expression profiles and new metabolic subgroups of benign meningioma with potential clinical relevance. Forty benign and fourteen atypical meningioma tissue samples were included in the study. We obtained metabolic profiles by NMR and recurrence after surgery information for all of them. We measured gene expression by oligonucleotide microarray measurements on 19 of them. To our knowledge, this is the first time that distinct gene expression profiles are reported for benign meningioma molecular subgroups with clinical correlation. Our results show that metabolic aggressiveness in otherwise histological benign meningioma proceeds mostly through alterations in the expression of genes involved in the regulation of transcription, mainly the LMO3 gene. Genes involved in tumor metabolism, like IGF1R, are also differentially expressed in those meningioma subgroups with higher rates of membrane turnover, higher energy demand and increased resistance to apoptosis. These new subgroups of benign meningiomas exhibit different rates of recurrence. This work shows that benign meningioma with metabolic aggressiveness constitute a subgroup of potentially recurrent tumors in which alterations in genes regulating critical features of aggressiveness, like increased angiogenesis or cell invasion, are still no predominant. The determination of these gene expression biosignatures may allow the early detection of clinically aggressive tumors.

Meningiomas are often considered benign tumors curable by surgery, but most recurrent meningiomas correspond to histologic benign tumors. Because alterations in chromosome 14 among others have suggested clinical aggressiveness and recurrence, determining both the molecular phenotype and the genetic profile may help distinguish tumors with aggressive metabolism. The aim of this study was to achieve higher specificity in the detection of meningioma subgroups by measuring chromosomal instabilities by fluorescence in situ hybridization and cytogenetics and metabolic phenotypes by high-resolution magic angle spinning spectroscopy. We studied 46 meningioma biopsies with these methodologies. Of these, 34 were of WHO grade 1 and 12 were of WHO grade 2. Genetic analysis showed a subgroup of histologic benign meningioma with chromosomal instabilities. The metabolic phenotype of this subgroup indicated an aggressive metabolism resembling that observed for atypical meningioma. According to the metabolic profiles, these tumors had increased energy demand, higher hypoxic conditions, increased membrane turnover and cell proliferation, and possibly increased resistance to apoptosis. Taken together, our results identify distinct metabolic phenotypes for otherwise benign meningiomas based on cytogenetic studies and global metabolic profiles of intact tumors. Measuring the metabolic phenotype of meningioma intact biopsies at the same time as histopathologic analysis may allow the early detection of clinically aggressive tumors., (©2010 AACR.)

Meningiomas are neoplasms that arise from the leptomeningeal covering of the brain and spinal cord, accounting for 15%-20% of CNS tumors. The WHO classifies meningiomas into three histological grades: benign, atypical, and anaplasic in accordance with the clinical prognosis. Atypical and anaplasic meningiomas tend to recur. Sometimes, meningiomas with histological diagnosis of benign meningioma show clinical characteristics of atypical meningioma. In this context, high-resolution magic-angle spinning (HR-MAS) spectroscopy of intact tissue from brain tumor biopsies has shown great potential as a support diagnostic tool. In this work, we show differences between benign and atypical meningiomas in HR-MAS molecular profiles of meningioma biopsies. Metabolic differences between meningioma grades include changes in the levels of glutathione. Glutathione role in cancer is still unclear, as it may act both as protective and pathogenic factor. Glutamine and glutamate, which are related to glutathione metabolism and have been associated with tumor recurrence, are also increased in atypical meningiomas. Other metabolites associated with tumor malignancy that show statistically significant differences between benign and atypical meningiomas include phosphocholine and phosphoethanolamine. Overall, this work suggests that the additional information obtained by NMR metabolomics applied to biopsies of human meningiomas may be useful for assessing tumor grade and determining optimum treatment strategies.

Meningiomas are tumors of the central nervous system with a great morphological heterogeneity. They are generally benign, and have the capacity to progress to a higher histological grade (atypical and anaplastic), which is associated with an increase in biological aggressivity and/or capacity to recur. Citogenetically this evolution is characterized by total or partial monosomy 22 in the early phase, continued by numerical and structural changes during tumor progression. In this study, we present a review of 85 cases of meningiomas: 43 benign, 28 atypical and 14 anaplastic. We study the clinical and histopathological features, and their correlation with cytogenetie abnormalities present in these tumors. Numerical aberrations such as monosomy of chromosome 10, 14 and 18, and structural abnormalities such as deletions on 1p are directly associated with a higher agressivity of tumors. An association of aberatons on 1p and chromosome 14 are more commonly found in atypical and anaplastic meningiomas. These facts imply that the presence of complex karyotypes progressively increases from grade I to grade III meningiomas. Furthermore, these karyotypes are common in recurrent tumors.

Deletion of 1p is associated with histological progression to meningiomas. Detection of this alteration may be a predicting factor for recurrences in this tumor. We present 8 meningiomas from four patients: the original tumor and the first recurrence in one patient, and the first and second recurrences in the other three were studied. We compared results of monosomy 22 and deletion of chromosome 1p with cytogenetic methods and fluorescence in situ hybridization (FISH) analysis obtained from slides of direct preparations, of cultured cells and slides of touch preparations. The cytogenetic study showed normal chromosome 22 and deletion on 1p32 in both samples of one patient; only monosomy 22 in both recurrences in another patient, and normal karyotypes with different non-clonal anomalies in the other tumors. However, with FISH analysis, monosomy 22 in both recurrences of three patients was demonstrated, as well as the loss of 1p in all tumors. These results were more evident in the analysis of direct and touch preparations than in those of cultured cells.