Molecular diagnosis and treatment of meningiomas: an expert consensus (2022)

ABSTRACT

Meningiomas are the most common primary intracranial neoplasm with diverse pathological types and complicated clinical manifestations. The fifth edition of the WHO Classification of Tumors of the Central Nervous System (WHO CNS5), published in 2021, introduces major changes that advance the role of molecular diagnostics in meningiomas. To follow the revision of WHO CNS5, this expert consensus statement was formed jointly by the Group of Neuro-Oncology, Society of Neurosurgery, Chinese Medical Association together with neuropathologists and evidence-based experts. The consensus provides reference points to integrate key biomarkers into stratification and clinical decision making for meningioma patients.

REGISTRATION

Practice guideline REgistration for transPAREncy (PREPARE), IPGRP-2022CN234.

Synthesizing Molecular and Immune Characteristics to Move Beyond WHO Grade in Meningiomas: A Focused Review

No portion of this manuscript has previously been presented. Meningiomas, the most common primary intracranial tumors, are histologically categorized by the World Health Organization (WHO) grading system. While higher WHO grade is generally associated with poor clinical outcomes, a significant subset of grade I tumors recur or progress, indicating a need for more reliable models of meningioma behavior. Several groups have developed risk scores based on molecular or immunologic characteristics. These classification schemes show promise, with several models preliminarily demonstrating similar or superior accuracy to WHO grading. Improved understanding of immune system recognition and targeting of meningioma subtypes is necessary to advance the predictive power, as well as develop new therapies. Here, we characterize meningioma molecular drivers, predictive of recurrence and progression, and describe specific aspects of the immune response to meningiomas while highlighting critical questions and ongoing research. Relevant manuscripts of interest were identified using a systematic approach and synthesized into this focused review. Finally, we summarize the ongoing and completed clinical trials for immunotherapy in meningiomas and offer perspective on future directions.

Outcomes of Preserving the Hypertrophic Arachnoid Membrane in the Brain-meningioma Interface: Long-term Follow-up

Abnormal hypertrophic arachnoid membranes are often observed in the brain–meningioma interface during microsurgery. They contain fibrosis and tumor cell clusters; however, preservation of the membranes does not always cause recurrence from the brain surface, and the optimal treatments in the interface remain unclear. We investigated the incidence of recurrence on the brain surface following extra-arachnoid dissection with an approach emphasizing preservation of the arachnoid membranes in meningiomas of World Health Organization (WHO) Grade I. The features of dissection cleavages in the interface were prospectively recorded at surgery. The patients were followed up with MR imaging regularly. In total, 111 patients were included. The median follow-up time was 97.0 (interquartile range [IQR] 70.0–124.0) months. The cleavages in the interface were classified into three subgroups: the Extra-H group (n = 56) with extra-arachnoid resection and preservation of hypertrophic arachnoid membranes, the Extra-N group (n = 39) with extra-arachnoid resection having normal membranes, and the Subpial resection group (n = 16). Tumors recurred in 13 (11.7%) patients at both the brain and dura mater (n = 1) or at the dura mater alone (n = 12). The median recurrence-free survival (RFS) of all recurrences was significantly related to the Simpson grades (P <0.01). For brain surface recurrence, the median RFS was not related to the subgroups. The Karnofsky Performance Scores (KPSs) significantly improved in the patients except for the Subpial group at 3 months after surgery. This study revealed that hypertrophic arachnoid membranes preserved on the brain surface rarely caused recurrence from the brain in WHO Grade I meningiomas after a long-term follow-up.

Single-Session Stereotactic Radiosurgery for Large Benign Meningiomas: Medium-to Long-Term Results

BACKGROUND

The use of stereotactic radiosurgery for the treatment of intracranial meningiomas has been established as an effective and safe treatment modality. Larger meningiomas typically are managed by surgery followed by radiosurgery. Treatment of large meningiomas (usually defined as >10 cc) by stereotactic radiosurgery has been investigated in some recent reports, either by single-session, volume-staged, or the hypofractionation technique. We sought to assess the long-term efficacy and safety of single-session stereotactic radiosurgery for large (10 cc or more) intracranial benign meningiomas.

PATIENTS AND METHODS

In this retrospective study, we included 273 patients with large benign meningiomas (≥10 cc) who were treated by single-session SRS and followed up for more than 2 years. Tumors were in a basal location in 228 patients (84%). There were 161 tumors (59%) in the perioptic location. The median tumor volume was 15.5 (10-57.3 cc [interquartile range {IQR} 12.3 cc]). The median prescription dose was 12 Gy (9-15 Gy [IQR 1 Gy]).

RESULTS

The median follow-up period was 6.1 years (2-18 years [IQR 5.5 years]). The tumor control rate was 90%. The progression-free survival at 5 and 10 years was 96% and 81%, respectively, for the whole cohort. Among 161 patients with perioptic meningiomas, favorable (better/stable) visual outcome was reported in 155 patients (96%) and unfavorable (worse) outcome in 6 patients (4%). Temporary adverse radiation effects were observed in 41 patients (15%) but only 16 (6%) were symptomatic.

CONCLUSIONS

Stereotactic radiosurgery provides an effective and safe treatment option for large meningiomas.

Metabolic alterations in meningioma reflect the clinical course

Background

Meningiomas are common brain tumours that are usually defined by benign clinical course. However, some meningiomas undergo a malignant transformation and recur within a short time period regardless of their World Health Organization (WHO) grade. The current study aimed to identify potential markers that can discriminate between benign and malignant meningioma courses.

Methods

We profiled the metabolites from 43 patients with low- and high-grade meningiomas. Tumour specimens were analyzed by nuclear magnetic resonance analysis; 270 metabolites were identified and clustered with the AutoPipe algorithm.

Results

We observed two distinct clusters marked by alterations in glycine/serine and choline/tryptophan metabolism. Glycine/serine cluster showed significantly lower WHO grades and proliferation rates. Also progression-free survival was significantly longer in the glycine/serine cluster.

Conclusion

Our findings suggest that alterations in glycine/serine metabolism are associated with lower proliferation and more recurrent tumours. Altered choline/tryptophan metabolism was associated with increases proliferation, and recurrence. Our results suggest that tumour malignancy can be reflected by metabolic alterations, which may support histological classifications to predict the clinical outcome of patients with meningiomas.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07887-5.

Metabolomic Profile of Aggressive Meningiomas by Using High-Resolution Magic Angle Spinning Nuclear Magnetic Resonance

Meningiomas are in most cases benign brain tumors. The WHO 2016 classification defines three grades of meningiomas. This classification had a prognosis value because grade III meningiomas have a worse prognosis value compared to grades I and II meningiomas. However, some benign or atypical meningiomas can have a clinical aggressive behavior. There are currently no reliable markers which allow distinguishing between the meningiomas with a good prognosis and those which may recur. High-resolution magic angle spinning (HRMAS) spectrometry is a noninvasive method able to determine the metabolite profile of a tissue sample. We retrospectively analyzed 62 meningioma samples by using HRMAS spectrometry (43 metabolites). We described a metabolic profile defined by a high concentration for acetate, threonine, N-acetyl-lysine, hydroxybutyrate, myoinositol, ascorbate, scylloinositol, and total choline and a low concentration for aspartate, glucose, isoleucine, valine, adenosine, arginine, and alanine. This metabolomic signature was associated with poor prognosis histological markers [Ki-67 ≥ 40%, high histological grade and negative progesterone receptor (PR) expression]. We also described a similar metabolomic spectrum between grade III and grade I meningiomas. Moreover, all grade I meningiomas with a low Ki-67 expression and a positive PR expression did not have the same metabolomic profile. Metabolomic analysis could be used to determine an aggressive meningioma in order to discuss a personalized treatment. Further studies are needed to confirm these results and to correlate this metabolic profile with survival data.

Advanced Imaging of Intracranial Meningiomas

Although typically not necessary for the diagnosis of intracranial meningiomas, advanced imaging techniques, including perfusion and diffusion imaging, spectroscopy, and nuclear medicine imaging, can help confirm the diagnosis of intracranial meningiomas, especially for meningiomas that do not exhibit the typical anatomic imaging findings. Advanced imaging techniques also have the potential to be able to differentiate between the subtypes of meningiomas, predict clinical aggressiveness of the tumor, and better characterize response to treatment. Although no advanced imaging technique has been able to definitively subclassify meningiomas, current results are encouraging and may be helpful in surgical planning.

Alterations of oxidative phosphorylation in meningiomas and peripheral nerve sheath tumors

BACKGROUND

Changes in the mode of aerobic energy production are observed in many solid tumors, though the kinds of changes differ among tumor types. We investigated mitochondrial energy metabolism in meningiomas and peripheral nerve sheath tumors, taking into consideration the histologic heterogeneity of these tumors.

METHODS

Oxidative phosphorylation (OXPHOS) complexes and porin (a marker for mitochondrial mass) were analyzed by immunohistochemical staining of meningiomas (n = 76) and peripheral nerve sheath tumors (schwannomas: n = 10; neurofibromas: n = 4). The enzymatic activities of OXPHOS complexes and citrate synthase were determined by spectrophotometric measurement. Western blot analysis of OXPHOS complexes, porin, and mitochondrial transcription factor A was performed. Furthermore, mitochondrial DNA copy number was determined.

RESULTS

The tumors differed with regard to mitochondrial energy metabolism. Low levels of a subset of OXPHOS complexes were frequently observed in World Health Organization grade I meningiomas (percent of cases with a reduction; complex I: 63%; complex II: 67%; complex IV: 56%) and schwannomas (complex III: 40%, complex IV: 100%), whereas in neurofibromas a general reduction of all complexes was observed. In contrast, expression of complexes III and V was similar to that in normal brain tissue in the majority of tumors. Mitochondrial mass was comparable or higher in all tumors compared with normal brain tissue, whereas mitochondrial DNA copy number was reduced.

CONCLUSIONS

The reduction of OXPHOS complexes in meningiomas and peripheral nerve sheath tumors has potential therapeutic implications, since respiratory chain-deficient tumor cells might be selectively starved by inhibitors of glycolysis or by ketogenic diet.

Masked hypodiploidy in anaplastic meningiomas by duplication of the original clone found in atypical meningiomas: illustration of the evolution of genetic alterations

Meningiomas are common, usually benign neoplasms of the central nervous system. Atypical and anaplastic meningiomas can be aggressive, show more rapid growth, and a greater propensity to recur following resection. General consensus believes that genetic abnormalities leading to anaplastic transformation are present at initial tumor presentation; however, this has not been demonstrated by array-comparative genome hybridization. We confirm the hypothesis by showing the evolution of genetic alterations in the transformation of an atypical meningioma to an anaplastic meningioma. Additionally, we provide potential genes responsible for malignant transformation of meningiomas, which, with further research, may provide diagnostic and therapeutic implications.

Proposal for a new risk stratification classification for meningioma based on patient age, WHO tumor grade, size, localization, and karyotype

BACKGROUND

Tumor recurrence remains the major clinical complication of meningiomas, the majority of recurrences occurring among WHO grade I/benign tumors. In the present study, we propose a new scoring system for the prognostic stratification of meningioma patients based on analysis of a large series of meningiomas followed for a median of >5 years.

METHODS

Tumor cytogenetics were systematically investigated by interphase fluorescence in situ hybridization in 302 meningioma samples, and the proposed classification was further validated in an independent series of cases (n = 132) analyzed by high-density (500K) single-nucleotide polymorphism (SNP) arrays.

RESULTS

Overall, we found an adverse impact on patient relapse-free survival (RFS) for males, presence of brain edema, younger patients (<55 years), tumor size >50 mm, tumor localization at intraventricular and anterior cranial base areas, WHO grade II/III meningiomas, and complex karyotypes; the latter 5 variables showed an independent predictive value in multivariate analysis. Based on these parameters, a prognostic score was established for each individual case, and patients were stratified into 4 risk categories with significantly different (P < .001) outcomes. These included a good prognosis group, consisting of approximately 20% of cases, that showed a RFS of 100% ± 0% at 10 years and a very poor-prognosis group with a RFS rate of 0% ± 0% at 10 years. The prognostic impact of the scoring system proposed here was also retained when WHO grade I cases were considered separately (P < .001).

CONCLUSIONS

Based on this risk-stratification classification, different strategies may be adopted for follow-up, and eventually also for treatment, of meningioma patients at different risks for relapse.

Gene expression profiles of metabolic aggressiveness and tumor recurrence in benign meningioma

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.

Her2neu amplification associates with Co-deletion 1p/14q in recurrent meningiomas

BACKGROUND

The current methods to predict recurrence and aggressive behaviour of meningiomas rely mainly on histological grading, histological subtype, proliferative index, as well as brain invasion. In many instances, histological grade alone fails to predict recurrence in the grade I and grade II meningiomas. Deletions of 1p and 14q have previously been reported to correlate with poor prognosis in terms of either recurrence or higher histological grades. The Her2neu (ErbB2) amplification has been shown to be a useful predictor of aggressive behaviour in breast and ovarian tumours, but its significance in meningioma is so far uncertain.

METHOD

In order to determine the cytogenetic differences between 22 recurrent and 25 non-recurrent meningiomas of all grades, we used fluorescent in situ hybridization (FISH) DNA probes for 1p36, 14q11.2 and 17q11.2-12 (Her2neu) on formalin fixed paraffin embedded (FFPE) tissue from the Brain Tumour Tissue Bank (BTTB), London Health Science Center (LHSC).

RESULTS

We showed a positive association for meningioma recurrence correlated with 1p36 deletion plus or minus 14q 11.2 deletions in all grades of meningiomas. The Her2neu amplification was strongly associated with 1p/14q co-deletion in cases of recurrent meningiomas, especially the higher grade tumours.

CONCLUSION

These cytogenetic markers can be applied in addition to histological grading for predicting the risk of recurrence and biological behaviour.

Fatty acid synthase is a predictive marker for aggressiveness in meningiomas

Meningiomas are the most frequent intracranial tumors. Although most are benign WHO grade I tumors, grade II and III tumors are aggressive and survival is poor. Treatment options for grade II and III meningiomas are limited, and molecular targets are few. The re-programming of metabolic pathways including glycolysis, lipogenesis, and nucleotide synthesis is a hallmark of the physiological changes in cancer cells. Because fatty acid synthase (FAS), the enzyme responsible for the de-novo synthesis of fatty acids, has emerged as a potential therapeutic target for several cancers, we investigated its involvement in meningiomas. We subjected 92 paraffin-embedded samples from 57 patients with grade I, 18 with grade II and III, and six with radiation-induced tumors to immunohistochemical study of FAS. Whereas its expression was increased in grade II and III meningiomas (62.9 %) compared with grade I tumors (29.8 %) (chi-squared test: p < 0.001), FAS was expressed in grade I tumors with a high MIB-1 index and infiltration into surrounded tissues. All radiation-induced meningiomas expressed FAS and its expression was positively correlated with the MIB-1 index (p < 0.005). Our findings suggest that increased FAS expression reflects the aggressiveness of meningiomas and that it may be a novel therapeutic target for treatment of unresectable or malignant tumors.

Metabolic aggressiveness in benign meningiomas with chromosomal instabilities

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.

Tumor grade-related NDRG2 gene expression in primary and recurrent intracranial meningiomas

Approximately 30% of all primary CNS tumors are meningiomas. Depending on histological type, meningiomas can recur as follows: benign--with five-year recurrence of 5%, atypical--recurrence approximately 40%, and anaplastic with recurrence of 50-80%. In an attempt to understand the molecular mechanism of meningioma recurrence we investigated the N-Myc downstream-regulated gene 2 (NDRG2), which has recently been described as important in suppressing cellular carcinogenesis in different types of cancer. The objective of the study was to investigate NDRG2 gene expression at the mRNA level in primary and recurrent meningiomas as a potential marker of tumor aggressiveness, malignancy, and recurrence. Primary and recurrent meningiomas of WHO grades I, II, and III from 35 patients operated on between 2005 and 2008 year at the Department of Neurosurgery of Kaunas Medical University Hospital (Lithuania) were studied. Using the qRT-PCR method we measured NDRG2 gene expression at the mRNA level in primary (n = 24) and recurrent (n = 11) meningiomas. Statistically significant differences in NDRG2 gene expression level were observed between primary and recurrent meningioma groups (P < 0.05) and between benign (WHO grade I) and atypical (WHO grade II) meningiomas (P < 0.05). No statistically significant differences were observed (P > 0.05) among histological subtypes of benign (WHO grade I) meningiomas: fibrous, meningothelial, and transitional. In accordance with our results, reduction of NDRG2 gene expression at the mRNA level could help to explain malignant progression and predisposition to recurrence in meningiomas.

Metabolic characterization of primary and metastatic ovarian cancer by 1H-MRS in vivo at 3T

(1)H-MRS was performed on 12 women (age range 45-72) with ovarian cancer of FIGO stage 3 or above using a 3T MRI system with an 8-channel cardiac receive coil. Respiratory-triggered PRESS-localized spectra (TE = 144 ms) were obtained separately from an ovarian mass and from metastatic disease. Peak areas were quantified relative to unsuppressed water using LCModel and spectra were discarded if LCModel reported signal-to-noise ratio (SNR) < 3 or if no metabolites were reported with standard deviation (SD) < 30%. The cystic fraction of each voxel was estimated by thresholding T(2)-weighted images, and this was used both to correct the reported metabolite concentrations and to calculate an expected SNR of choline using the measured SNR of water. Choline was detected in 10/12 primary tumors and 5/11 metastatic lesions (range 2.0-16.6 mM). Of the 8/23 failures, 7 had a predicted choline SNR < 2, confirming that the failure to detect choline could be explained by technical problems. Glycine was observed in one benign lesion. (1)H-MRS can be used to quantify choline in primary and metastatic masses in ovarian cancer, but the moderately high rate of failure to detect choline necessitates careful recording of data quality parameters to discriminate true from false negatives.

Using ex vivo proton magnetic resonance spectroscopy to reveal associations between biochemical and biological features of meningiomas

Object

The goal in this study was to determine if proton (1H) MR spectroscopy can differentiate meningioma grade and is associated with interpretations of biological behavior; the study was performed using ex vivo high-resolution spectra indicating metabolic characteristics.

Methods

Sixty-eight resected tissue samples of meningiomas were examined using ex vivo 1H MR spectroscopy. Of these meningiomas, 46 were WHO Grade I, 14 were WHO Grade II, and 8 were WHO Grade III. Fifty-nine were primary meningiomas and 9 were recurrences. Invasion of adjacent tissue (dura mater, bone, venous sinus, brain) was found in 32 cases. Thirty-nine meningiomas did not rapidly recur (as defined by expansion on MR imaging within a 5-year follow-up period), whereas rapid recurrence was confirmed in 24 meningiomas, and follow-up status was unknown in 5 cases.

Results

The absolute concentrations of total alanine and creatine were decreased in high-grade compared with low-grade meningiomas, as was the ratio of glycine to alanine (all p < 0.05). Additionally, alanine and the glycine/alanine ratio distinguished between primary and recurrent meningiomas (all p < 0.05). Finally, the absolute concentrations of alanine and creatine, and the glycine/alanine and choline/glutamate ratios were associated with rapid recurrence (p < 0.05).

Conclusions

. These data indicate that meningioma tissue can be characterized by metabolic parameters that are not typically identified by histopathological analysis alone. Creatine, glycine, and alanine may be used as markers of meningioma grade, recurrence, and the likelihood of rapid recurrence. These data validate a previous study of a separate group of Grade I meningiomas.

Myoinositol Trends in Different Types of Brain Lesions

Myoinositol (Myo) is a not yet well known metabolite detected using short echo time proton magnetic resonance spectroscopy (HMRS). We examined the role of Myo in 26 patients with new diagnosis of brain lesions including tumors, inflammatory and infectious processes. Histological confirmation of the diagnosis was obtained during gross total surgical resection or stereotactic biopsy of the lesions. The highest ratios of Myo/Cr were found in the hemangiopericytoma and meningioma followed by cortical dysplasia, low grade gliomas, gliobastomas, lymphomas, demyelinating lesions and toxoplasmosis. There was no Myo detected in the cases of metastasis and abscess. Increased Myo levels correlated with low grade gliomas suggesting its potential use in the differentiation of glial tumor. Myo demonstrated a unique pattern in hemangiopericytoma.

Prospective serial proton MR spectroscopic assessment of response to tamoxifen for recurrent malignant glioma

OBJECTIVE

Early prediction of imminent failure during chemotherapy for malignant glioma has the potential to guide proactive alterations in treatment before frank tumor progression. We prospectively followed patients with recurrent malignant glioma receiving tamoxifen chemotherapy using proton magnetic resonance spectroscopic imaging ((1)H-MRSI) to identify intratumoral metabolic changes preceding clinical and radiological failure.

METHODS

We performed serial (1)H-MRSI examinations to assess intratumoral metabolite intensities in 16 patients receiving high-dose oral tamoxifen monotherapy for recurrent malignant glioma (WHO grade III or IV) as part of a phase II clinical trial. Patients were followed until treatment failure, death, or trial termination.

RESULTS

Patients were officially classified as responders (7 patients) or non-responders (9 patients) 8 weeks into treatment. At 8 weeks, responders and non-responders had different intratumoral intensities across all measured metabolites except choline. Beyond 8 weeks, metabolite intensities remained stable in all responders, but changed again with approaching disease progression. Choline, lipid, choline/NAA, and lactate/NAA were significantly elevated (P < 0.02), while creatine (P < 0.04) was significantly reduced, compared to stabilized levels on average 4 weeks prior to failure. Lactate was significantly elevated (P = 0.036) fully 8 weeks prior to failure. In one patient who was still responding to tamoxifen at the conclusion of the trial, metabolite intensities never deviated from 8-week levels for the duration of follow-up.

CONCLUSIONS

Characteristic global intratumoral metabolic changes, detectable on serial (1)H-MRSI studies, occur in response to chemotherapy for malignant glioma and may predict imminent treatment failure before actual clinical and radiological disease progression.

Implicating chromosomal aberrations with meningioma growth and recurrence: results from FISH and MIB-I analysis of grades I and II meningioma tissue

The fluorescence in situ hybridization (FISH) technique was used in 111 WHO grades I and II meningioma patients. Clinical, radiological, pathological, and immunohistochemical data were compared to aberrations of chromosomes 1p, 14q, and 22q determined by FISH. Significant differences for MIB-1 labeling were found between grades I and II tumors (p < 0.001), and between grade I tumors that recurred and those that did not recur (p < 0.001). Chromosomal aberrations were detected with FISH analysis in nearly 50% of grade I, and in 93% of grade II meningiomas. The numbers of chromosomal aberrations correlated significantly to MIB-1 (p < 0.001), with signs of grossly invasive tumor growth (p < 0.001), and with tumor recurrence (p < 0.01). The findings suggest that adding FISH analysis may allow better prediction of possible meningioma recurrence and may be a useful adjunct for therapy decisions.