Comparison of MIB-1 (Ki-67) antigen and bromodeoxyuridine proliferation indices in meningiomas

Current decision-making in meningiomas

The incidence of meningiomas is rising and the number of incidental cases is increasing steadily. The efficiency and the safety of each treatment strategy are also improving over time. Therefore the indications to treat meningiomas are constantly changing. The aim of meningioma treatment is keeping the patient fully functional while achieving long-term relief or prevention from problems related to intracranial tumor growth. This chapter reviews the natural history and treatment results and aims to put together the information for the most objective decision-making in treating meningiomas. Factors acting on the treatment decision such as anatomical localization, symptomatology, variations in tumor biology, recurrence status, age and co-morbidities, operative gains, and patient preference are individually discussed.

Natural history of intracranial meningiomas

We know that the extent of resection is the greatest predictor of long-term survival. However, the potential tradeoff for gross total resection in difficult locations is diminished quality of life. Benign subtotally resected or small incidentally discovered meningiomas may be followed clinically especially in the elderly. In addition, radiosurgery plays a role in the treatment of meningiomas as a primary treatment modality, or as a salvage therapy. Decisions regarding management should be made with an understanding of the natural history and rate of growth. In this chapter we review the known meningioma epidemiology as well as the growth patterns of meningiomas based upon location.

Meningioma Tumor Microenvironment

The tumor microenvironment consists of noncancerous cells, such as immune cells and fibroblasts, and the proteins produced by these cells as well as the extracellular matrix components in the environment around a tumor. Tumor influences the behavior of the cells present in the surrounding environment, while the cells in the tumor microenvironment modulate the evolution of the tumor. Little is known about the microenvironment of meningioma, the most common benign intracranial tumor. Here, we review the current knowledge of the tumor microenvironment of meningioma and discusses its importance in meningioma tumorigenesis as well as in the designation of novel therapeutic approaches.

Impact of CyberKnife Radiosurgery on Median Overall Survival of Various Parameters in Patients with 1-12 Brain Metastases

Introduction

This study’s objective is to assess various patient, tumor and imaging characteristics and to compare median overall survival (OS) of 150 patients with 1-12 brain metastases post-CyberKnife radiosurgery (CKRS) (Accuray, Sunnyvale, California) alone.

Methods

Charts of 150 patients, from 2009-2014, treated with only CKRS for brain metastases were reviewed retrospectively for patient, tumor, and imaging characteristics. Parameters included demographics, Eastern Cooperative Oncology Group (ECOG) performance scores, number and control of extracranial disease (ECD) sites, cause of death (COD), histology, tumor volume (TV), and post-CKRS whole brain radiotherapy (WBRT). The imaging characteristics assessed were time of complete response (CR), partial response (PR), stable imaging or local failure (LF), and distal brain failure (DBF). The primary tumor Ki-67s of the breast carcinoma brain metastasis patients, who had the longest median OS of any group, were recorded when available.

Results

The predominant age group for the 150-patient cohort was the younger 17-65 years of age category, which was represented by 94 (62.7%). The 150-patient group had slightly more males, 79 (52.7%). The majority of 111 (74%) patients had an ECOG score of 1, 39 (26%) had 1 ECD site and uncontrolled ECD occurred in 112 (74.7%). The main COD was ECD in 106 (70.7%). The prevalent tumor histology was non-small cell lung carcinoma (88 of 150, 58.7%). The most common TV was 0-0.5 ccs (48 of 150, 32%). The majority of 125 (83.3%) patients did not undergo post-CKRS WBRT. Imaging outcomes were local control (LC) (CR, PR, or stable imaging) in 119 (79.3%), of whom 38 (25.3%) had CR, 56 (37.3%) PR and 25 (16.7%) stable imaging; LF was the outcome in 31 (20.7%) and DBF occured in 83 (55.3%). The median OS was 13 months. Patients 17-65 years of age had a median OS of 13 months, while those 66-88 years, had 12 months. Females versus males had median OS of 15 versus 12 months. The most prolonged median OS of 21.5 months occurred in those with an ECOG score of 0. Patients with two ECD sites had a median OS of 14.5 months, while those with controlled ECD, 20.5 months. Patients with breast cancer brain metastases had the longest median OS of 23 months. The median OS for each of three (0-0.5 ccs, 0.6-1.5 ccs, 1.6-4.0 ccs) of four CKRS TV quartiles was 13 months and for those with 4.1-28.5 ccs, 10 months. Median OS for patients with versus without post-CKRS WBRT was 23 versus 12 months. The longest median OS of 18.5 months for post-CKRS imaging outcomes was in patients with CR; those with LF had a median OS of 11.5 months. Of nine patients with breast carcinoma brain metastases with available Ki-67s from primary tumor resections, the Ki-67 values were ≥ 34% for four patients with CR, PR and stable imaging outcomes, and < 34% for five patients with LF.

Conclusions

An ECOG score of 0, ECD control, breast carcinoma brain metastasis histology. undergoing WBRT post-CKRS and CR imaging outcomes, each resulted in a longer median OS. The Ki-67 proliferation indices from primary breast carcinoma resection correlated well with the brain imaging outcomes in a small preliminary study in the present study's breast carcinoma patients with brain metastases.

Comparison of the DWI and Gd-EOB-DTPA-enhanced MRI on assessing the hepatic ischemia and reperfusion injury after partial hepatectomy

OBJECTIVE

To compare two different imaging media, diffusion weighted imaging (DWI) with apparent diffusion coefficient (ADC) and Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) with perfusion parameters K^trans, K^ep, and relative contrast enhancement index (RCEI), in assessing the liver function via ischemia/perfusion injury (IRI) + partial hepatectomy rat model.

METHODS

Rats underwent 0, 30 and 60min of ischemia/reperfusion with 30% of hepatectomy before subjected to Gd-EOB-DTPA-enhanced MRI in addition to ^99mTc-GSA scintigraphy. For ^99mTc-GSA scintigraphy test, the receptor index LHL15, modified receptor index and the blood clearance index HH15 were recorded. Apparent diffusion coefficient (ADC) was evaluated by using both mono- and bi-exponential models, and perfusion parameters K^trans, K^ep, and RCEI were measured. Liver function is tested by measuring activity of serum ALT, AST and PT. Histological analysis was performed by H&E and Ki-67 staining.

RESULTS

^99mTc-GSA dynamic imaging analysis demonstrated that LHL15 was increased and HH15 was decreased as the extension of ischemia/reperfusion time. ADC value estimated by MRI was significantly increased (P<0.05) in 30min IRI group compared with 0min and 60min IRI groups, respectively. K^trans value was gradually and significantly decreased (P<0.05) as the extension of IRI time, but there was no significant difference (P>0.05) in K^ep value between at 30min and 60min IRI, and RCEI value was significantly higher (P<0.05) in 30min IR compared with 0min and 60min IRI group. Serum level of ALT, AST and PT were gradually and significantly (P<0.05) increased as the extension of IRI time. Histological analysis showed that there was a remarkable difference between 30min and 60min IRI, as protein expression of Ki-67 was significantly higher (P<0.05) in 30min IRI group.

CONCLUSION

Fast ADC bi-exponential model in DWI and RCEI in Gd-EOB-DTPA-enhanced MRI showed the good correlation in assessment of liver function after partial hepatectomy, showing consistency with our histological findings. The K^trans in Gd-EOB-DTPA-enhanced MRI could be a potent parameter for assessing the early ischemic injury, but not the severity of the hepatic injury, in accordance with the correlation with our biochemical findings.

Surgically resected skull base meningiomas demonstrate a divergent postoperative recurrence pattern compared with non-skull base meningiomas

OBJECTIVE The objective of this study was to identify the natural history and clinical predictors of postoperative recurrence of skull base and non-skull base meningiomas. METHODS The authors performed a retrospective hospital-based study of all patients with meningioma referred to their institution from September 1993 to January 2014. The cohort constituted both patients with a first-time presentation and those with evidence of recurrence. Kaplan-Meier curves were constructed for analysis of recurrence and differences were assessed using the log-rank test. Cox proportional hazard regression was used to identify potential predictors of recurrence. RESULTS Overall, 398 intracranial meningiomas were reviewed, including 269 (68%) non-skull base and 129 (32%) skull base meningiomas (median follow-up 30.2 months, interquartile range [IQR] 8.5-76 months). The 10-year recurrence-free survival rates for patients with gross-total resection (GTR) and subtotal resection (STR) were 90% and 43%, respectively. Skull base tumors were associated with a lower proliferation index (0.041 vs 0.062, p = 0.001), higher likelihood of WHO Grade I (85.3% vs 69.1%, p = 0.003), and younger patient age (55.2 vs 58.3 years, p = 0.01). Meningiomas in all locations demonstrated an average recurrence rate of 30% at 100 months of follow-up. Subsequently, the recurrence of skull base meningiomas plateaued whereas non-skull base lesions had an 80% recurrence rate at 230 months follow-up (p = 0.02). On univariate analysis, a prior history of recurrence (p < 0.001), initial WHO grade following resection (p < 0.001), and the inability to obtain GTR (p < 0.001) were predictors of future recurrence. On multivariate analysis a prior history of recurrence (p = 0.02) and an STR (p < 0.01) were independent predictors of a recurrence. Assessing only patients with primary presentations, STR and WHO Grades II and III were independent predictors of recurrence (p < 0.001 for both). CONCLUSIONS Patients with skull base meningiomas present at a younger age and have less aggressive lesions overall. Extent of resection is a key predictor of recurrence and long-term follow-up of meningiomas is necessary, especially for non-skull base tumors. In skull base meningiomas, recurrence risk plateaus approximately 100 months after surgery, suggesting that for this specific cohort, follow-up after 100 months can be less frequent.

Histopathological and Immunohistochemical Evaluation of Meningiomas with Reference to Proliferative Markers p53 and Ki-67

INTRODUCTION

Meningiomas are slow growing primary central nervous system (CNS) tumours attached to the duramater, which arise from the meningothelial cells of the arachnoid. Grading of meningioma based on histological findings assisted with supplementary immunohistochemical studies, predicts the prognosis of meningioma with good precision.

AIM

To evaluate proliferative markers and correlate with various histological subtypes and grade.

MATERIALS AND METHODS

A total of 224 meningiomas, diagnosed between January1995 and October 2011were graded according to WHO 2007 criteria. Immunostaining for p53 and Ki-67 markers were performed on 100 cases.

RESULTS

There was female predominance. There were 194 Grade I, 24 Grade II and 6 Grade III meningiomas. Brain invasion noted in 18(8%) meningiomas predominantly in grade III followed by grade II. Recurrence was seen in 7 (3.1%) cases, most common in psammomatous followed by angiomatous meningioma. Immunostaining showed p53 positivity in 72.5% of grade I, 83.3% of grade II and all the cases of grade III tumours. Ki-67 Labelling Index (LI) consistently increased from grade I to grade III tumours.

CONCLUSION

p53 and Ki-67 LI correlated well with increasing histological grade and biological behaviour of meningioma.

Effects of supplemental vitamin D and calcium on normal colon tissue and circulating biomarkers of risk for colorectal neoplasms

This brief review, based on an invited presentation at the 17th Workshop on Vitamin D, is to summarize a line of the author's research that has been directed at the intertwined missions of clarifying and/or developing vitamin D and calcium as preventive agents against colorectal cancer in humans, understanding the mechanisms by which these agents may reduce risk for the disease, and developing 'treatable' biomarkers of risk for colorectal cancer. The biological plausibility and observational and clinical trial evidence for vitamin D and calcium in reducing risk for colorectal neoplasms, the development of pre-neoplastic biomarkers of risk for colorectal neoplasms, and the clinical trial findings from the author's research group on the efficacy of vitamin D and calcium in modulating these biomarkers are summarized. Regarding the latter, we tested the efficacy of 800 IU (20μg) of vitamin D3 and 2.0g of calcium daily, alone and combined vs. placebo over 6 months on modulating normal colon tissue and circulating hypothesis-based biomarkers of risk for colorectal neoplasms in a randomized, double-blind, placebo-controlled, 2×2 factorial design clinical trial (n=92). The tissue-based biomarkers were measured in biopsies of normal-appearing rectal mucosa using immunohistochemistry with quantitative image analysis, and a panel of circulating inflammation markers was measured using enzyme-linked immunoassays (ELISA). Statistically significant proportional tissue increases in the vitamin D group relative to the placebo group were found in bax (51%), p21 (141%), APC (48%), E-cadherin (78%), MSH2 (179%), the CaSR (39%), and CYP27B1 (159%). In blood, there was a 77% statistically significant decrease in a summary inflammation z-score. The findings for calcium were similar to those for vitamin D. These findings indicate that supplemental vitamin D3 or calcium can favorably modulate multiple normal colon tissue and circulating hypothesis-based biomarkers of risk for colorectal neoplasms in sporadic colorectal adenoma patients. This article is part of a Special Issue entitled '17th Vitamin D Workshop'.

Analysis of progression and recurrence of meningioma using (11)C-methionine PET

OBJECTIVE

The recurrence rate of meningioma after surgery is high, and progression is often observed. The risk factors for recurrence and progression are not clear. We evaluated the risk factors for recurrence and progression in meningioma using (11)C-methionine (MET) positron emission tomography (PET).

METHODS

Thirty-seven patients (mean follow-up, 80 months) with an intracranial meningioma were enrolled. MET PET was performed before treatment between 1995 and 2010, and patients were followed up in an out-patient clinic. Surgery was performed in 33 patients, and a wait-and-see approach was taken in four patients. We evaluated the extent of tumor resection, location, WHO grade, Ki-67 labeling index, and lesion to normal ratio (LN ratio) of MET uptake.

RESULTS

Six of the surgical cases had a recurrence, and two of the observation-only patients had tumor progression. A high LN ratio of MET uptake was a significant risk factor for recurrence and progression with univariate analysis. The area under the curve of receiver operating characteristic curve for the LN ratio of MET uptake was 0.754, and the optimal cutoff value was 3.18 (sensitivity 63 %, specificity 79 %). With multivariate analysis, a high LN ratio of MET uptake, non-gross total resection, and a high WHO grade were significant risk factors for progression and recurrence.

CONCLUSION

A high LN ratio of MET uptake was a risk factor for tumor progression and recurrence. The advantage of MET PET is that it is not invasive and can easily be used to evaluate the whole tumor.

Computer-aided volumetric analysis as a sensitive tool for the management of incidental meningiomas

INTRODUCTION

Meningiomas are typically slow-growing lesions that, depending on the location, can be relatively benign. Knowing their exact rate of growth can be helpful in determining whether surgery is necessary.

METHODS

In this study we retrospectively reviewed the meningioma practices of the two senior authors (JR, MR). Our goal was to measure meningioma growth using a variety of methods (linear using diameters, and volumetric using the computer-aided perimeter and cross-sectional diameter methods) to compare rates of growth among the methods. Of 295 meningioma patients seen over an 8-year period, we identified a cohort of 31 patients with at least 30 months of follow-up. Volumes were calculated using medical imaging software with T1 post-contrast magnetic resonance imaging. Doubling times and growth rates were calculated.

RESULTS

Of the 31 patients, 26 (84%) were shown to have growing meningiomas. The perimeter methodology measured higher growth rates than the diameter method for both doubling times as well as percentage annual growth (p<0.01). The mean doubling time was 13.4 years (range, 2.1–72.8 years) and 17.9 years (range, 4–92.3 years) comparing perimeter and diameter methods, respectively. The mean percentage of annual growth was 15.2% (range, 1.8–61.7%) and 5.6% (range, 0.7–12.2%), comparing perimeter and diameter methods, respectively. Linear growth was calculated at 0.7 mm/year.

CONCLUSION

Overall, we found that computer-aided perimeter methods showed a more accurate picture of tumor progression than traditional methods, which generally underestimated growth.

Primary mediastinal atypical meningioma: report of a case and literature review

Meningiomas are common neoplasms arising from the central nervous system meninges. On the other hand, primary ectopic meningiomas are extremely rare and usually limited to the head and neck region or to the paravertebral soft tissues. Their occurrence in the mediastinum is even rarer. Until now, only 4 cases of primary mediastinal meningioma have been reported in the literature searched on Medline. Because of its rarity and intriguing pathogenesis, we report here a case of primary mediastinal meningioma that was treated by surgical resection. The clinical features, treatment, pathological findings, and prognosis are analyzed, and the literature on ectopic meningioma is reviewed.

Recurrence and outcome in skull base meningiomas: do they differ from other intracranial meningiomas?

BACKGROUND AND OBJECTIVES

Meningiomas have diverse presentations and the skull base harbors the most difficult of them to operate upon. The objective of this study was to learn whether the recurrence and outcome of these tumors may differ based on their location.

DESIGN

Consecutive admissions with intracranial meningiomas between 1999 and 2004 were considered according to their location, WHO grade, recurrence, and outcome following treatment.

RESULTS

There were 83 skull base meningiomas and 86 at other locations. In 22 cases of skull base tumors there was recurrence (26.5%), while 15% (13) of the other group showed recurrence. There was no statistically significant difference in the outcome between the two groups; though skull base lesions had a better outcome based upon a raw count. Only 5.1% of skull base meningiomas in comparison to 10.6% of non-skull base meningiomas had death or significant morbidity. Increasing age was associated with poor outcome (p < 0.001) while recurrence was a function of skull base location (p < 0.03) on logistic regression analysis.

CONCLUSION

Skull base meningiomas can be operated upon with good outcome, which is comparable to the convexity meningiomas. Except for the increasing age, skull base location does not contribute to increased mortality or morbidity.

Enhanced antitumor effect of coincident intravesical gemcitabine plus BCG therapy in an orthotopic bladder cancer model

OBJECTIVES

To evaluate the antitumor effect of the coincident administration of intravesical gemcitabine (Gem) plus bacillus Calmette-Guérin (BCG) in an orthotopic bladder cancer model.

METHODS

We evaluated the cytotoxic effect of gemcitabine against MBT-2 cells in vitro. Orthotopic tumors were established by implanting MBT-2 cells into the bladder of syngeneic female C3H mice. Intravesical Gem administration was evaluated at various doses: 0 mg (control); 1, 2, 4, and 8 mg (n = 8 for each group). Next, a comparative evaluation of tumor growth among the control, Gem-alone, BCG-alone, and combined Gem + BCG groups was performed (n = 16 for each group). Therapy was administered at 3-day intervals starting on day 5 and repeated 6 times. To evaluate the proliferative activity among the groups, Ki-67 immunostaining of the tumor was performed.

RESULTS

Gemcitabine exhibited a dose-dependent antitumor effect. Of the 8 mice in each group treated with a dose of 0, 1, 2, 4, or 8 mg of Gem, 1, 4, 4, 4, 5, and 4 mice failed to develop tumors and survived, respectively. The combination of Gem + BCG (54.1 ± 9.4 days) provided a significant survival advantage compared with BCG-alone (39.0 ± 16.4 days) (P = .02). Ki-67 expression, representing tumor proliferation, was significantly lower in the combined Gem + BCG group than in the BCG-alone group (P < .01).

CONCLUSIONS

Our results suggest that intravesical Gem + BCG treatment induces an enhanced antitumor effect against bladder tumors.

Enhanced antitumor effect of combination intravesical mitomycin C and bacillus Calmette-Guerin therapy in an orthotopic bladder cancer model

Intravesical immunotherapy with bacillus Calmette-Guerin (BCG) is currently the most successful adjuvant agent for the treatment and/or prophylaxis of non-muscle-invasive bladder cancer (NMIBC). However, NMIBCs recur in 60-70% of cases and 30% of these recurrent tumors present with a higher grade and more invasive properties. Patients that do not respond to intravesical BCG therapy are considered to be a challenge for urologists. Thus, novel conservative possibilities should be explored. To test the efficacy of a novel therapeutic approach, we examined the antitumor effect of combination therapy by intravesical administration of mitomycin C (MMC) plus BCG, infusing the two drugs simultaneously, in an orthotopic bladder cancer model. Intravesical BCG and MMC administration showed a dose-dependent survival (n=8 per group). The combination of MMC and BCG provided a significant survival advantage compared to the BCG-alone (p=0.035) and MMC-alone groups (p=0.040) (n=8 per group). The group with combined MMC/BCG exhibited a survival period similar to that achieved with an amount eight times higher that of BCG (n=10 per group). Ki-67 labeling index of cancer cells, showing tumor proliferation, was significantly lower in the combined group compared to the BCG-alone (p<0.05), MMC-alone (p<0.01) and control groups (p<0.01). No difference was detected between the combined group and the BCG-alone group with regard to CD3, T-cell infiltration and CD68 macrophage activity. The combined MMC/BCG treatment decreased the tumor appearance rate, improved the survival period and reduced the cellular proliferation rate in tumors compared to the BCG-alone treatment. The results suggest that the combined intravesical MMC/BCG treatment induced an enhanced antitumor effect against bladder tumors. The combined MMC/BCG treatment also showed a survival period similar to that achieved using a dose eight times higher of BCG-alone.

The significance of Ki-67/MIB-1 labeling index in human meningiomas: a literature study

Histology alone does not always predict the clinical outcome of human meningiomas. Determination of proliferative activity has therefore become an important diagnostic and prognostic tool to identify more aggressive meningiomas, and the Ki-67/MIB-1 monoclonal antibody has become widely used. The aim of this study was to assess the prognostic value of the Ki-67/MIB-1 labeling index (LI) in human meningiomas by a search in the literature. In PubMed/Medline databases, 53 articles were found, and they all showed positive correlations between Ki-67/MIB-1 LI and histological malignancy grade. The average mean labeling indices were 3%, 8%, and 17% for grade I-III meningiomas, respectively. There was, however, considerable overlap of indices between the malignancy groups. Concerning recurrence, meningiomas with a labeling index beyond 4% may indicate an increased relapse rate. Consequently, Ki-67/MIB-1 LI represents a useful predictor of tumor grade and risk of recurrence, however, it must be interpreted cautiously in the individual tumor.

Drug delivery with carbon nanotubes for in vivo cancer treatment

Chemically functionalized single-walled carbon nanotubes (SWNT) have shown promise in tumor-targeted accumulation in mice and exhibit biocompatibility, excretion, and little toxicity. Here, we show in vivo SWNT drug delivery for tumor suppression in mice. We conjugate paclitaxel (PTX), a widely used cancer chemotherapy drug, to branched polyethylene glycol chains on SWNTs via a cleavable ester bond to obtain a water-soluble SWNT-PTX conjugate. SWNT-PTX affords higher efficacy in suppressing tumor growth than clinical Taxol in a murine 4T1 breast cancer model, owing to prolonged blood circulation and 10-fold higher tumor PTX uptake by SWNT delivery likely through enhanced permeability and retention. Drug molecules carried into the reticuloendothelial system are released from SWNTs and excreted via biliary pathway without causing obvious toxic effects to normal organs. Thus, nanotube drug delivery is promising for high treatment efficacy and minimum side effects for future cancer therapy with low drug doses.

MIB-1 immunolabeling: a valuable marker in prediction of benign recurring meningiomas

Histological analysis has limited value to predict biological behavior of meningiomas. We investigated the utility of cell proliferative indicator in the evaluation of histologically benign meningiomas. We selected 25 benign non-recurrent meningiomas, 15 benign recurrent meningiomas after complete surgical resection, 30 atypical meningiomas, and 15 anaplastic meningiomas out of 384 cases studied. MIB-1 Labeling Index was evaluated by two methods: Highest Labeling Index (HLI) and Random Labeling Index (RLI). There was no dependable histological parameter to predict recurrence among benign-looking meningiomas. HLI had significant difference when compared with RLI in all categories. The mean MIB-1 HLI values +/- SD were 3.47 +/- 2.0% for benign meningiomas, 5.08 +/- 4.0% for atypical meningiomas and 11.66 +/- 7.06% for anaplastic meningiomas. In comparison, the mean MIB-1 HLI of benign non-recurrent meningiomas were 2.66 +/- 1.7% and with recurrence were 4.21 +/- 2.78% (P = 0.0339). Using receiver operating characteristic, it was seen that neoplasm recurred with the MIB-1 HLI of > 2.6 having the sensitivity of 64.6% and specificity of 68% among benign (grade I) meningiomas. MIB-1 positive tumor cells were maximally aggregated at the periphery of excised specimen. MIB-1 HLI, integrated with standard histopathology can provide better information about the disease biological nature in benign meningiomas.

Recurrences of meningiomas: predictive value of pathological features and hormonal and growth factors

OBJECTIVE

Recurrence of apparently completely resected benign meningiomas is a rather frequent event, the mechanisms of which are still unclear. The aim of this study is to define the pathological features, proliferation indexes, growth factors and hormone receptor expression in predicting the meningioma recurrence.

METHODS

Two groups of 50 completely resected benign WHO I meningiomas, with and without recurrence respectively, have been reviewed. Tumor location, consistency, vascularity, and histological types have been considered. Immunohistological studies include mitotic index (MI), Ki-67 LI, estrogen and progesterone receptors (ER and PR), Vascular Endothelial Growth Factor (VEGF), Epidermal Growth Factor (EGF), and Bcl-2. All these factors have been correlated with the recurrence.

RESULTS

The tumor recurrence was not correlated with the patient age, tumor location, consistency, vascularity and histology. There was not difference in the histological pattern between local and diffuse recurrences. M.I. and Ki-67 LI were significantly correlated with the recurrence (P<0.0001). PR negativity had a strong predictive value of recurrence (P<0.0001), whereas the ER status was not relevant. VEGF and EGF-R were not correlated with the recurrence of meningiomas, whereas the Bcl-2 protein positivity showed a tendency to the significativity (P=0.0294). The negative association between Bcl-2 and PR is an interesting finding of our study.

CONCLUSIONS

Higher MI and Ki-67 LI and PR negativity are predictive factors of recurrence of benign (WHO I) completely resected meningiomas, particularly when Bcl-2 positivity is associated.

Proliferation potential of spinal meningiomas

OBJECTIVES

The goal of the present study was to quantitatively assess the proliferation index and progesterone receptor status of spinal versus intracranial meningiomas and to determine if these biological indicators can describe the clinical behavior of these tumors. This information could provide the spinal surgeon with important additional information concerning surgical management and follow-up recommendations for the individual patient.

METHODS

The study group consisted of 26 patients with spinal and 241 patients with intracranial meningiomas. Patients with atypical or anaplastic tumors as well as with neurofibromatosis type II were excluded from the study. Furthermore both groups were matched according to age, sex and resection grade (total resection according the Simpson classification). Proliferation index (Ki-67 Labelling index [LI]) and progesterone-receptor (PR) status of spinal and intracranial meningiomas were compared. Clinical charts including surgical and histological records and imaging studies were reviewed. Correlations with histological subtype, intratumoral calcifications, tumor vascularity and recurrence-free survival were analyzed.

RESULTS

Compared to the spinal group with a mean Ki-67 LI of 2.48% and a positive PR-status of 46%, proliferation rates of intracranial meningiomas were significant higher (Ki-67 LI 3.6%; P-value 0.041). No significant difference in PR status was seen (spinal PR-status 46%, P-value 0.261). Furthermore spinal meningiomas were less vascularized and showed less intratumoral calcifications. Time to recurrence was similar in spinal and intracranial tumors.

CONCLUSION

Spinal and intracranial meningiomas differ in their proliferation activity but not in their PR status. However, despite lower proliferation rates, time to recurrence in spinal and cranial meningiomas is comparable in totally excised tumors. Further studies are needed to determine the role of other biological indicators in spinal meningioma growth and response to therapy.

Edema and malignancy in meningiomas

PURPOSE

In recent years there have been many attempts to define a subset of aggressive malignant meningiomas based on histopathology and imaging technologies. The purpose of this study was to evaluate the level of peritumoral edema and its volume using the imaging technologies, computer tomography and magnetic resonance imaging, and correlate these results with the histological WHO classification. Reported causes of tumoral edema and its relationships to the histological characteristics were also reviewed.

METHODS

The cases of 55 patients with meningiomas who underwent surgery at the Hospital das Clinicas (Fac Med Univ Sao Paulo) between September 1993 and September 1997 were reviewed. The level of edema according to the classification of Ide et al. (1995) was compared to the histological WHO classification.

RESULTS

Classification of the degree of edema was: level 0 edema--28 cases ; level I edema--19 cases; level II edema--8 cases. Histological classification was: benign meningioma--43 cases; atypical meningiomas--11 cases; malignant meningioma--1 case. There was a significant (P=.0089) correlation between the degree of tumoral edema and the histological characteristics.

CONCLUSIONS

These results suggest that the degree of edema as revealed by computer tomography and magnetic resonance imaging can be an important clinical predictive factor for the histological grade of the meningioma.

The Mitosis-Specific Antibody Anti-Phosphohistone-H3 (PHH3) Facilitates Rapid Reliable Grading of Meningiomas According to WHO 2000 Criteria

Mitotic figure (MF) counting is the most objective criterion for grading of meningiomas according to the 2000 World Health Organization (WHO) classification. However, the search for the area(s) of highest mitotic activity is tedious, and there is high interobserver variability in differentiating MF from apoptotic cells. We tested the utility of the mitosis-specific marker phosphohistone-H3 (PHH3) to enhance rapid recognition of MFs and quick reliable grading of meningioma. Fifty-four archival meningiomas (26 benign, 20 atypical, 8 anaplastic) were reclassified according to current WHO criteria. PHH3-immunostained MFs were counted the same way as in hematoxylin and eosin-stained sections. Anti-PHH3-labeled MFs were easily seen and permitted quick identification of the area(s) of highest mitotic activity. Count results (mean) show a strong correlation between both methods: benign, hematoxylin and eosin 1.4, PHH3 2.2; atypical, hematoxylin and eosin 9.0, PHH3 15.9; anaplastic, hematoxylin and eosin 22.4, PHH3 34.1. PHH3 counting yielded greater sensitivity and in 12 cases (22.2%) suggested a change in grade (increased 9; lowered 3). All cases in which PHH3 lowered the grade were from older blocks, suggesting a loss of antigen preservation. PHH3 immunostaining facilitates the rapid reliable grading of meningiomas by focusing attention on the most mitotically active areas and by allowing easy and objective differentiation of MFs from apoptotic nuclei.

Coexpression of hepatocyte growth factor/scatter factor (HGF/SF) and its receptor cMET predict recurrence of meningiomas

Hepatocyte growth factor/scatter factor (HGF/SF) and its receptor, the cMET tyrosine kinase participate in cancer invasion, angiogenesis and metastasis in a wide variety of neoplastic cells. Meningioma is a bening tumour, however, it has a high rate of recurrence after surgery; the most important factor to predict relapse is the extent of surgical resection, several other potentially predictive factors have been studied with poor results. We examined by immunohistochemistry the expression of HGF/SF and its cMET receptor in a group of patients with benign meningioma with or without recurrence (n = 17 and n = 25, respectively), after a minimal follow-up of least 6 years. Expression and coexpression of HGF/SF and cMET were compared with cell proliferation index, vascular density and clinical outcome. Coexpression of HGF/SF and cMET in meningiomas had a significant association with cell proliferation index and with recurrence (P < 0.037). Determination of HGF and cMET coexpression in meningiomas could be used as a predictor of recurrence.

Malignant progression in meningioma: documentation of a series and analysis of cytogenetic findings

Object. The malignant progression of benign tumors is well documented in gliomas and other systemic lesions. It is also well known that some meningiomas become progressively aggressive despite their original benign status. The theory of clonal evolution is widely believed to explain malignant progression in meningioma; however, the data used to explain stepwise progression have typically been derived from the cytogenetic analysis of different types of tumors of different grades and in different patients. In this study, the authors examined the data obtained in a group of patients with meningiomas that showed clear histopathological progression toward a higher grade of malignancy and then analyzed the underlying cytogenetic findings.

Methods. Among 175 patients with recurrent meningiomas, 11 tumors showed a histopathological progression toward a higher grade that was associated with an aggressive clinical course. Six tumors progressed to malignancy and five to the atypical category over a period averaging 112 months. Tests for MIB-1 and p53 and cytogenetic studies with the fluorescence in situ hybridization (FISH) method were performed in successive specimens obtained in four patients.

The MIB-1 value increased in subsequent samples of tumors. Cytogenetic analysis with FISH showed deletions of 22, 1p, and 14q. In all but one case, these aberrations were also present in the previous specimen despite its lower hispathological grade.

Conclusions. The authors documented the progression of meningiomas from benign to a higher histological grade. These tumors were associated with a complex karyotype that was present ab initio in a histologically lower-grade tumor, contradicting the stepwise clonal evolution model. Although it was limited to the tested probes, the FISH method appears to be more accurate than the standard cytogenetic one in detecting these alterations. Tumors that present with complex genetic alterations, even those with a benign histological grade, are potentially aggressive and require closer follow up.

Extracranially extended meningothelial meningiomas with a high MIB-1 index: A report of two cases

Meningiomas that extend from the meninges to the extracranial tissue and result in skull osteolysis have been known to take an aggressive clinical course. Two such cases in elderly patients are reported. Case 1 is an 82-year-old woman who had undergone removal of the parasagittal meningioma (meningothelial meningioma with 5% of MIB-1 index) 4 years and 6 months previously, developed recurrence of the tumor that extended to extracranial soft tissue. Biopsy obtained from the subcutaneous tissue showed an atypical meningothelial meningioma with 20% of MIB-1 index. In case 2 an 84-year-old man, who developed rapidly progressing dementia and gait disturbance, the MRI study revealed an intracranial-extraaxial right frontal tumor with an extracranial extension resulting in skull osteolysis. Pathological examination of the totally resected tumor identified meningothelial meningioma, but MIB-1 index of the intracranial portion of the tumor was less than 0.1%, while that of the extracranial portion was approximately 15%. Although the meningiomas presently reported failed to show histological features of malignancy, the high MIB-1 index indicated that they were rapidly growing tumors. In the present report it is considered that meningioma cells that invade the skull and extracranial tissue are biologically aggressive and require total resection, as long as the condition of the patients is feasible for surgery.

Proliferation rate of intracranial meningiomas as defined by the monoclonal antibody MIB-1: correlation with peritumoural oedema and other clinicoradiological and histological characteristics

Paraffin-embedded surgical specimens from 55 meningiomas were immunostained after microwave processing using the streptavidin/peroxidase method and the monoclonal antibody (moAb) MIB-1 to the Ki-67 antigen. The authors assessed proliferative labelling index (LI) from a series of surgically removed meningiomas using immunohistochemical methods and MIB-1, and they correlated this index with clinical, radiological, and histological factors. No relationship was found between LI, sex, age, resection and histological grades, or volume. Symptoms, location, and peritumoural oedema did have a significant relationship to the MIB-1 LI. The symptomatic patients, i.e. those with tumours at the base of the skull and with GR3 peritumoural oedema (grade 3), had a greater chance of higher MIB-1 LI. It was proven that the increase of one unit in peritumoural oedema classification gave an increased risk of 3.312 and an LI greater than 3%. The authors also discuss the different methods of evaluating LIs in meningiomas, based on the available literature.

Proliferative activity of canine mast cell tumours evaluated by bromodeoxyuridine incorporation and Ki-67 expression

The proliferative activity of 91 canine mast cell tumours was assessed on the basis of the Ki-67 positive index (Ki-67 PI) and mitotic index (MI) and, in 15 cases, also by the labelling index of bromodeoxyuridine (BrdU; an analogue of tritiated thymidine) incorporated in vivo into S-phase cells. BrdU and Ki-67 were detected immunohistochemically. The tumours were graded histologically (I, II or III). The BrdU labelling index (BrdU LI) tended to increase as the grade became higher. In terms of the mean values of Ki-67 PI, significant differences were found between histological tumour grades I and II (P < 0.01) and between grades II and III (P < 0.01). In terms of mean MI, grades I and II were found to differ significantly (P < 0.05). With Spearman rank correlation coefficient and linear regression analysis, the BrdU LI and Ki-67 PI showed a highly significant correlation. This strong correlation indicated that Ki-67 was, like BrdU, a useful marker for proliferative potential in canine mast cell tumours; moreover, its use did not require the prior administration of any reagent to the live animal.

DNA topoisomerase II-alpha and cyclin A immunoexpression in meningiomas and its prognostic significance: an analysis of 263 cases

CONTEXT

Routine pathologic examination cannot distinctively predict the clinical course of meningiomas because even histologically benign tumors may recur after gross total resection. Therefore, numerous efforts have been made to evaluate the meningioma growth fraction and its prognostic value. However, a universally applicable proliferative marker for meningioma outcome is not yet a reality.

OBJECTIVE

To investigate the prognostic utility of 3 proliferative markers, namely, Ki-67, DNA topoisomerase II-alpha (topoII), and cyclin A in a representative series of intracranial meningiomas.

DESIGN

Two hundred sixty-three adult patients with intracranial meningiomas (208 benign, 42 atypical, and 13 anaplastic) were studied retrospectively. Tumor specimens were immunohistochemically examined with antibodies to Ki-67 (MM-1), topoII, and cyclin A. A computerized color image analyzer was used to count immunostained nuclei.

RESULTS

The topoII and cyclin A scores exhibited a close correlation with Ki-67 immunostaining. Significant differences between the indices for all 3 markers were noted among the 3 grades of meningiomas. The scores for all 3 markers were significantly different between recurrent and nonrecurrent meningiomas, including benign tumors that were treated with gross total resection. Recurrence-free survival was significantly reduced for cases with a Ki-67 labeling index (LI) of 4.4% or greater, a topoII LI of 3.2% or greater, and a cyclin A LI of 3.1% or greater. Multivariate analysis revealed that the risk of recurrence for the entire meningioma cohort was significantly associated with tumor grade (hazard ratio = 2.7; P =.004), topoII LI of 3.2% or greater (hazard ratio = 5.5; P <.001), and a cyclin A LI of 3.1% or greater (hazard ratio = 2.4; P =.01).

CONCLUSIONS

There is a close correlation in the expression of these 3 proliferative markers in meningiomas, and all of the markers showed a significant association with tumor grade, recurrence rate, and recurrence-free survival. Consequently, in addition to Ki-67, immunoexpression of topoII and cyclin A is available for predicting meningioma recurrence. Moreover, the topoII and cyclin A staining scores were found to be more sensitive predictors for meningioma progression than Ki-67 and, therefore, either of these 2 markers may prove to be clinically informative and useful.

Histopathology and MIB-1 labeling index predicted recurrence of meningiomas: a proposal of diagnostic criteria for patients with atypical meningioma

BACKGROUND

Although various histopathologic features have been associated with aggressive behavior or recurrence of meningiomas, there is little agreement about which features are the most important and in what combination. The objective of this study was to formulate diagnostic criteria for atypical meningioma.

METHODS

Eighty-three patients with meningiomas who underwent macroscopic total resection and had been followed until they developed recurrent disease or for at least 10 years were studied. Thirteen histopathologic parameters that related to recurrence of the tumor were evaluated in each patient. All possible combinations of histologic parameters that were related significantly to recurrence were used to formulate scoring models. The model that included the fewest parameters and that could distinguish tumor recurrence best within 10 years was chosen as the final model.

RESULTS

The final model included three parameters: loss of architecture, mitoses > or= 1.5/mm2, and necrosis. Of the 52 tumors with a score < 2 (0 or 1 of the 3 parameters), all except 1 tumor did not recur within 10 years, and they were all considered benign meningiomas. Of the 31 tumors with a score > or = 2 (2 or 3 of the 3 parameters), 94% recurred within 10 years (76% recurred within 5 years), and they were considered atypical meningiomas. The estimated 5-year and 10-year recurrence rates for the benign meningiomas were 0.0% and 1.9%, respectively, for benign meningiomas and 71.0% and 93.5%, respectively, for atypical meningiomas (P < 0.001). The estimated 5-year and 10-year mortality rates also were significantly different (0.0% and 0.0% vs. 22.1% and 26.7%, respectively; P < 0.001). The MIB-1 labeling index (LI) for the entire group studied ranged from 0.4 to 33.5 (mean LI, 8.4). Fifty-two tumors with an LI of < 10 did not recur within 10 years. Of the 31 tumors with an LI > or = 10, 97% recurred (71% within 5 years).

CONCLUSIONS

Histopathology and MIB-1 LI were able to predict clinical outcomes of patients with meningioma. The authors propose that atypical meningioma may be diagnosed when two of the following three criteria are present: loss of architecture, mitoses > or = 1.5/mm2, and necrosis.

Stromelysin-3 is expressed by aggressive meningiomas

BACKGROUND

Stromelysin-3 (ST3) that belongs to the metalloproteinase family is proposed to play a role in tumor invasion. The purpose of this work was to study the variation of ST3 expression in meningiomas.

METHODS

Twenty atypical meningiomas were retrieved from the Pathology Department's files at Hopital de Bellevue, Saint-Etienne, France. They were compared with 20 benign meningiomas randomly selected from the same file. The tumors were classified using standard histologic criteria. Frozen sections of the tumors were immunostained for ST3 and MIB-1 to evaluate the proliferative activity of tumor cells.

RESULTS

The study included 5 fibrous meningiomas, 10 transitional meningiomas, 20 syncitial meningiomas, 2 secretory meningiomas, 2 microcystic meningiomas, and 1 angiomatous meningioma. Stromelysin-3 was expressed within the stromal and neoplastic cells of only 1 benign meningioma and 13 atypical meningiomas. The MIB-1 proliferation index was significantly higher in the meningiomas expressing ST3 (Student t test: P < 0.001). The invasion of bone, muscle, and brain by meningiomas as well the recurrence were statistically correlated with their ST3 expression (Kruskal-Wallis nonparametric correlation test, P = 0.001 and P = 0.008, respectively).

CONCLUSIONS

Stromelysin-3 might play an important role in the invasiveness of meningiomas. Therefore, considering, ST3 in association with evaluation of the MIB-1 proliferating index may be an useful tool to assess the behavior of meningiomas.

Significance of MIB-1 staining indices in meningiomas: comparison of two counting methods

The authors evaluated the predictability of MIB-1 immunohistochemistry for growth and recurrences of meningiomas using two different counting methods: 1) in the area of the highest MIB-1 labeling (HL method) and (2) in randomly selected fields (RS method). The MIB-1 staining indices (SIs) determined by the HL method were approximately twice as high as those by the RS method, and the correlation coefficient between them was high (R = 0.86) in 139 meningiomas when transformed logarithmically. The differences in SIs in histologic grades were significant with either method. Tumor doubling time (Td) was calculated in 22 meningiomas from serial radiologic examinations. The RS method yielded a slightly higher correlation coefficient between log Td and log SI than the HL method. When the authors examined the predictability of recurrence in 112 totally removed meningiomas, the RS method distinguished the recurrent group more definitively. Several benign meningiomas with low SIs by the RS method exhibited focal accumulation of MIB-1-positive cells. Although they were assigned high MIB-1 values by the HL method, these meningiomas did not recur, and therefore obscured the prognostic importance of the MIB-1 value with the HL method. Focal accumulation of MIB-1-positive cells in meningiomas is not likely to correlate with their biologic aggressiveness.

MIB-1 staining index of pediatric meningiomas

OBJECTIVE

For adult meningiomas, the staining index (SI) for the anti-Ki-67 monoclonal antibody MIB-1 is well correlated with histological atypia and tumor recurrence. MIB-1 SIs for meningiomas in the pediatric population have not been previously reported. Meningiomas tend to be more histologically aggressive and to recur more frequently in children, compared with adults. The objectives of this study were to determine whether MIB-1 SIs are correlated with pathological atypia and recurrence among pediatric meningiomas and to compare the MIB-1 SIs of pediatric meningiomas with those of adult meningiomas.

METHODS

MIB-1 SIs were assessed on paraffin-embedded sections of 14 pediatric meningiomas (patient age, 2-17 yr), 5 of which contained atypical or malignant features. For comparison with benign pediatric meningiomas, MIB-1 SIs were also assessed on paraffin-embedded sections of 14 adult meningiomas (patient age, 38-90 yr), none of which displayed atypical or malignant features or recurred within a 5-month median follow-up period.

RESULTS

MIB-1 SIs of pediatric meningiomas ranged from 1.2 to 31.6% (median, 9.1%). Significant differences were observed between the MIB-1 SIs for tumors with atypical or malignant features (median, 12.3%; range, 7.0-31.6%) and those for tumors without atypia (median, 7.0%; range, 1.2-12.6%; P = 0.045). There were six recurrences after gross total resection, during a 36.5-month median follow-up period. All five of the tumors with pathological atypia recurred; one tumor without atypia recurred. Significant differences were observed between MIB-1 SIs for nonrecurrent tumors (median, 6.6%; range, 1.2-12.2%) and those for recurrent tumors (median, 12.5%; range, 7.0-31.6%; P = 0.012). The median MIB-1 SI for adult control specimens was 8.8% (range, 1.2-19.3%), which did not differ significantly from that for pediatric meningiomas without atypia (P = 0.68).

CONCLUSION

For this cohort of pediatric meningiomas, pathological atypia and the tendency to recur were correlated with elevated MIB-1 SIs. The median MIB-1 SI for pediatric meningiomas without histological atypia did not differ significantly from that for adult meningiomas without atypia, suggesting that the more aggressive clinical features of meningiomas in children may be attributable to factors other than the rate of cellular proliferation.

Prognostic significance of p53 and p21WAF1/CIP1 immunoreactivity and tumor micronecrosis for recurrence of meningiomas

Recurrence is an important factor for prognosis of meningioma patients, this also occurring with some lesions diagnosed histopathologically as benign. To analyze their relationships with clinicopathological factors, p53 and p21WAF1/CIP1 immunoreactivity, 80 meningiomas were classified into four groups with regard to the World Health Organization (WHO) histological classification and recurrence: 40 cases of Group I (typical type)-NR (no recurrence); five cases of Group I-R (recurrence); 20 cases of Group II (atypical or anaplastic type)-NR and 15 cases of Group II-R. Micronecrosis was detected in 25% of Group II-NR and 73.3% of Group II-R (P = 0.007, odds ratio (OR) = 8.25, 95% confidence interval (CI) = 1.79-38.01). Patients receiving radiation therapy had a lower risk of recurrence (P = 0.041, OR = 0.20, 95% CI = 0.05-0.85). Immunoreactivity for p53 protein was positive in 22% of Group I and 54% or Group II (P = 0.005), and in 80% of Group I-R and 15% of Group I-NR (P = 0.006, OR = 22.7, 95% CI = 2.15-239.4). p21WAF1/CIP1 protein was detected in 22% of Group I and 48% of Group II (P = 0.017), but with no link to recurrence. Multivariate analysis also showed p53 immunoreactivity in Group I (benign lesions) and micronecrosis in Group II (atypical/anaplastic meningiomas) to be strong prognostic factors for recurrence (P < 0.05). These results indicate that p53 immunoreactivity and micronecrosis can help predicting recurrence of meningiomas.

Prognostic value of proliferation index and expression of the RNA component of human telomerase (hTR) in papillary meningiomas

Papillary meningioma is a rare subtype of meningioma that often behaves aggressively. In order to characterize factors that may influence this behavior, we chose to compare MIB-1 labeling index (LI) and telomerase RNA localization (hTR) in papillary meningiomas, meningiomas, and atypical meningiomas. LI is now often used to supplement histologic grade in the evaluation of these lesions. More recent studies indicate that increased expression of hTR is detected in many neoplastic cells, and may play an essential role in cell immortalization. The study group consisted of five papillary meningiomas (and a recurrence in one case), 11 conventional meningiomas, and eight atypical meningiomas. Conventional meningiomas showed either negative or 1 + hTR. Atypical meningiomas showed 1 + hTR. Papillary meningiomas showed the highest hTR (five of six, including recurrence, 2-3+ and one 1+). Generally, the LI was very low for conventional meningiomas (< 2%). The LI of atypical meningiomas ranged from 3-19%, mean 12%, and from 5.5-17.5%, mean 11.75% for papillary meningiomas. LI differentiated between meningiomas, and papillary or atypical meningiomas. hTR further delineated papillary (moderate to high) from atypical meningiomas (low). The combined variable of LI and hTR expression could be a useful independent prognostic indicator in patients with papillary meningioma.

Apoptotic activity and bcl-2 immunoreactivity in meningiomas. Association with grade and outcome

We retrospectively evaluated 90 meningiomas for bcl-2 expression, apoptosis counts (per 10 high-power fields [HPF]), MIB-1 labeling indices (LI), and mitosis counts (per 10 HPF). Characteristics were as follows: 37 low-grade (benign) meningiomas: mean apoptosis count, 1.2; MIB-1 LI, 1.0; mitosis count, 0.1; and bcl-2 positivity, 40%; 29 atypical meningiomas: apoptosis count, 3.3; MIB-1 LI, 5.5; mitosis count, 2.2; and bcl-2 positivity, 62%; 24 malignant meningiomas: apoptosis count, 6.5; MIB-1 LI, 12.0; mitosis count, 6.0; and bcl-2 positivity, 67%. By univariate analysis, MIB-1 LI, apoptosis and mitosis counts, and tumor grade were associated significantly with death due to tumor; by multivariate analysis, only mitosis count was independently associated with death due to tumor. We compared similar data for 27 patients with nonrecurrent tumors and 32 patients with recurrent meningiomas. Histologic sections from the initially resected tumor and from the most recent recurrence were reviewed. Only the apoptosis count was significantly higher by univariate analysis in the initial resection specimens from tumors that ultimately recurred vs nonrecurrent tumors. Expression of bcl-2, MIB-1 LI, and mitosis count did not correlate with recurrence. By multivariate analysis, only extent of surgical resection was associated significantly with tumor recurrence. Although bcl-2 immunostaining was not associated statistically with outcome, bcl-2 positivity was more common in atypical and malignant meningiomas than in low-grade tumors.

Intracranial meningeal tumours in childhood: a clinicopathologic study including MIB-1 immunohistochemistry

Primary tumours of the meninges with a relatively high tendency for malignant behaviour are uncommon in childhood. This study concerns 18 cases of meningeal tumours in children under the age of 16, of which 13 were meningiomas and five were other tumours arising in the meninges. Meningiomas showed a preponderance in females as in adult series, and the majority were supratentorial in localisation. The percentage of meningeal tumours and meningiomas among all brain tumours in our centre were 3.72% and 2.69%, respectively. Four out of 13 meningiomas were fibroblastic, four were transitional, one was meningothelial, two were psammomatous and two were papillary meningiomas. Seven (38.8%) out of 18 tumours showed anaplastic features, including two papillary meningiomas, two hemangiopericytomas, one mesenchymal chondrosarcoma, one pleomorphic sarcoma and one anaplastic meningeal tumour. Papillary meningiomas with hemangiopericytoma-like solid areas were seen frequently in our cases (15.3%). Meningoangiomatosis was associated with two meningeal tumours. MIB1 (Ki-67) labelling indices (LIs) ranged between 0% and 13.6% (mean 1.83%) in benign, and between 1% and 20% (mean 7.2%) in malignant tumour, including papillary meningiomas. Mean MIB-1 LIs were 5.61% and 1.14% in non-recurrent and recurrent cases, respectively. MIB-1 LIs showed significant differences between benign and malignant meningeal tumours but no significant correlation either with prognosis or recurrence. Despite the fact that brain tumours are among the most common neoplasms of childhood, meningeal tumours are rare lesions, accounting for less than 2% of published series of intracranial neoplasms in childhood [5, 8, 18, 24, 30, 32]. It has been suggested that the clinical and pathological characteristics of meningiomas in this age group differ from those of adults [14, 18, 24, 45]. Besides meningiomas, there are a few reports of other meningeal tumours in childhood and difficulties in differential diagnosis may arise within this group, especially in anaplastic tumours [11, 13, 32, 44, 46]. One of the major problems in meningiomas and some tumours arising in the meninges is the discordance that arises between the histologic appearance of the tumour and behaviour [4]. Several studies have attempted to determine the proliferation potential of meningiomas, including immunohistochemical labelling with monoclonal antibodies to Ki-67, proliferating cell nuclear antigen (PCNA), and bromodeoxyuridine (BUdR); flow cytometric DNA analysis; or argyrophilic nucleolar organizer regions (AgNORs) counting [9, 10, 15, 19, 22, 26, 31, 35, 53]. The studies concerning proliferation markers have contradictory results [9, 10, 15, 26, 31, 42, 53]. MIB-1 detects the same or a similar epitope as the original antibody Ki-67 and reacts with a proliferation associated antigen expressed in all active parts of the cell cycle, G1, S, G2 and M (mitosis), but not in the G0 or quiescent phases [7]. In this study we examined the clinicopathological characteristics and MIB1 values of 18 meningeal tumours in children under the age of 16 years within the last 25 years (from 1970 to 1995).

Cell production rates in human tissues and tumours and their significance. Part 1: an introduction to the techniques of measurement and their limitations

In the past two decades, the technology of laser cytometry and use of the halogenated thymidine (HP) analogues bromodeoxyuridine and iododeoxyuridine as proliferation labels, have allowed us to quantify the rate of cell turnover in tissues and tumours, in clinical samples as in laboratory models. The principal studies have used injection of bromo- or iododeoxyuridine to measure cell production rates in vivo. Flow cytometry (FCM) has been used to estimate the S phase labelling index (LI) and the S phase duration (Ts) and calculate the cell production rate, represented by the potential doubling time (Tpot). This has allowed calculation of time-dependent indices of proliferation from single biopsies of HP pulse labelled human tissues and tumours. In the first part of this two-part review, we describe the technique and its limitations as a biological assay. The second part summarizes the knowledge gained about cell production rates and the relevance that this information may have to future investigative, prognostic and treatment strategies.

Noninvasive evaluation of the malignant potential of intracranial meningiomas performed using proton magnetic resonance spectroscopy

OBJECT

Controversy exists about correlations between histological tumor grade and magnetic resonance (MR) spectroscopy data. The authors studied single-voxel proton MR spectroscopy as a noninvasive way to evaluate grade of malignancy in intracranial meningiomas.

METHODS

The authors compared the results of MR spectroscopy with those derived by the MIB-1 staining index (SI) in 29 meningiomas. Proton MR spectroscopy was performed using stimulated echo acquisition and volume-localized solvent-attenuated proton nuclear MR sequences before surgery or other therapy. Twenty-four tumors were histologically benign (13 meningothelial, three fibrous, four transitional, three angiomatous, and one chordoid); four were atypical (Grade II), and one was papillary (Grade III). The mean MIB-1 SI in the benign group was significantly lower than those in the other groups (p = 0.0041). The mean choline-containing compound (Cho)/ creatine and phosphocreatine (Cr) ratios in the benign and nonbenign groups were 2.56+/-1.26 and 7.85+/-3.23, respectively (p = 0.0002). A significant linear correlation was observed between the Cho/Cr ratio and the MIB-1 SI (r0.05 = 0.74, p<0.001). Necrosis was present histologically in four of the five meningiomas classified either as atypical or papillary. Magnetic resonance spectroscopy revealed a methylene signal in these meningiomas that was not detected in benign meningiomas. Of the five meningiomas in which only a lactate signal was observed, two were benign and the MIB-1 SI in these two benign meningiomas was higher than the mean value for the benign group. Alanine, detected in 12 of 30 meningiomas, did not correlate with either tumor grade or Cho/Cr ratio.

CONCLUSIONS

Proton MR spectroscopy is a useful diagnostic method for determining the proliferative or malignant potential of meningiomas according to the Cho/Cr ratio. A lactate and/or methylene signal suggests a high-grade tumor.

Histopathologic features and MIB-1 labeling indices in recurrent and nonrecurrent meningiomas

BACKGROUND

Predicting the behavior of meningiomas based on histopathologic features alone has remained problematic.

DESIGN

This study retrospectively compared several histopathologic features and MIB-1 labeling indices (LIs) in recurrent meningiomas with those of nonrecurrent meningiomas. Six histopathologic features, including mitoses, necrosis, loss of architectural pattern, hypervascularity/hemosiderin deposition, prominent nucleoli, and nuclear pleomorphism, were compared between 32 recurrent and 27 nonrecurrent meningiomas using Fisher exact tests. MIB-1 LIs (% positive tumor cell nuclei) were compared using the Wilcoxon rank sum test.

RESULTS

The patients in the recurrent group included 26 women (mean age, 55 years), who developed 1 to 5 recurrences. Time intervals to the first recurrence ranged from 5 to 183 months (mean, 55 months). The nonrecurrent group included 21 women (mean age, 56 years), with follow-up ranging from 88 to 124 months (mean, 109 months). Of the histopathologic features evaluated, statistically significant differences between the recurrent and nonrecurrent groups were found only with respect to prominent nucleoli (P =.024) and nuclear pleomorphism (P <.001), both of which were more common in the recurrent group. In the recurrent group, 9 tumors were considered malignant (defined by brain invasion or metastasis) versus 2 of the nonrecurrent meningiomas. Nineteen percent of nonrecurrent tumors versus 41% of recurrent tumors had 2 or more of the 6 histopathologic features. MIB-1 LIs in the nonrecurrent group ranged from 0 to 8.3 (mean, 1.5) and were generally lower than those in the recurrent group (range, 0-32.5; mean, 5.4); no statistical difference was identified between these groups. No statistically significant difference with regard to histology or MIB-1 LIs was noted between the initially excised recurrent tumor and the most recently resected recurrence.

CONCLUSIONS

Of the histopathologic features examined, only prominent nucleoli and nuclear pleomorphism were found to be statistically more common in recurrent than nonrecurrent meningiomas. The mean MIB-1 LI was higher in the recurrent than in the nonrecurrent group, although there was no statistical difference between means and there was clear overlap with regard to MIB-1 LI ranges.

MIB-1 labeling indices in benign, aggressive, and malignant meningiomas: a study of 90 tumors

Predicting tumor behavior in meningiomas based on histology alone has been problematic. This study retrospectively compares histology and MIB-1 (cell proliferation marker) labeling indices (LI) in benign, aggressive, and malignant meningiomas. Six histological features, including mitoses, necrosis, loss of pattern, hypervascularity/hemosiderin deposition, prominent nucleoli, and nuclear pleomorphism, were compared in 90 meningiomas (Fisher's exact test). Tumors with two or more of the above features were designated as aggressive meningiomas. Malignant meningiomas were characterized by brain invasion or metastasis. The MIB-1 LIs (% positive tumor cell nuclei) were compared between the three groups (Kruskal-Wallis test, Wilcoxon two-sample test). Of the benign meningiomas (n=37; mean age, 54 years), 41% had one of the six histological features, with nuclear pleomorphism (n=10) being the most frequent. The aggressive tumors (n=29; mean age, 61 years) were characterized by nuclear pleomorphism (n=28), mitoses (n=20), necrosis (n=16), loss of pattern (n=16), prominent nucleoli (n=6), and hypervascularity/hemosiderin deposition (n=5). Malignant tumors (n=24; mean age, 59 years) were characterized by nuclear pleomorphism (n=22), mitoses (n=21), loss of pattern (n=21), necrosis (n=21), nucleoli (n=17), and hypervascularity/hemosiderin deposition (n=3). Significant differences were found between the aggressive and malignant groups with regard to loss of pattern, necrosis, and nucleoli (P=.0043, .011, and .00029, respectively). Mean MIB-1 LIs for the benign, aggressive, and malignant groups were 1.0% (range, 0 to 5.5%),5.5% (range, 0.1 to 32.5%), and 12.0% (range, 0.3 to 32.5%), respectively. Differences in the mean MIB-1 LI between groups were statistically significant, with P values of <.0001 (benign v aggressive) and .0012 (aggressive v malignant). Mean MIB-1 LIs for recurrent versus nonrecurrent tumors were 7.1% (range, 0 to 32.5%) versus 3.8% (range, 0 to 20.9%) (P=.32). The mean MIB-1 LI for patients who were alive with or without tumor was 6.2% (range, 0 to 32.5%) versus a mean MIB-1 LI of 14.2% (range, 2.8% to 32.5%) for patients who died of or with tumor (P=.0013). In conclusion, (1) There is a statistically significant difference in the increasing MIB-1 LI means between benign, aggressive, and malignant meningiomas and between patients who were alive versus those who died; (2) there is some overlap in MIB-1 LI ranges between groups, which warrants caution in interpreting an individual MIB-1 LI in a given tumor.

MIB-1 (Ki-67) index and transforming growth factor-alpha (TGF alpha) immunoreactivity are significant prognostic predictors for meningiomas

Mitotic index > 6, proliferating cell nuclear antigen (PCNA) index > 5%, high tumour grade and absence of progesterone receptors (PR) are significant predictors for poor outcome in meningiomas. Since MIB-1 (Ki-67) is a more specific cell proliferation marker, and overexpression of TGF-alpha is also associated with tumour progression, we compared the prognostic significance of these factors with the other indices. Intracranial meningiomas from 21 men and 36 women (age 54.5 +/- 1.7, mean +/- SEM) were classified as 24 benign, 24 atypical and nine malignant. Twenty-one of the 57 tumours recurred (mean interval to recurrence was 57.3 +/- 13.1 months). The mean follow-up period for patients without tumour recurrence was 81.9 +/- 8.7 months. MIB-1 labelling index (LI) was expressed as percentage of labelled nuclei to total tumour nuclei counted in the most densely labelled areas. Analysis of variance revealed significant differences between tumour grades for MIB-1 labelling indices (0.75 +/- 0.21 for benign, 3.2 +/- 0.57 for atypical 6.04 +/- 1.48 for malignant; P < or = 0.0066), and between malignant and non-malignant meningiomas for TGF alpha staining scores (P < or = 0.029). MIB-1 LI also correlated with mitotic and PCNA indices (P < or = 0.0001), but not with age of the patients. Male patients had higher tumour MIB-1 LI than females (P < or = 0.0128). Univariate analysis indicated that MIB-1 LI > 3%, TGF alpha score > 4 (scoring scale 0-5), mitotic index > 6, and negative PR status were significant factors for worse outcome. Higher MIB-1 LI, TGF alpha score and mitotic index as continuous variables were also significant negative predictors. With multivariate analysis, both MIB-1 LI and TGF alpha score remained significant factors when paired with all other variables: TGF alpha or MIB-1 LI, respectively, mitosis, PCNA, tumour grade, PR status, age, sex, postoperative radiation therapy. We conclude that MIB-1 LI and TGF alpha score are important independent prognostic indicators for patients with meningiomas.

Apoptosis is associated with atypical or malignant change in meningiomas. An in situ labelling and immunohistochemical study

AIMS

Although necrosis is an important phenomenon with implications for grading and prognostication in meningiomas, the alternate form of cell death, apoptosis, has not been extensively studied. In this series, we aimed to determine whether apoptosis in meningiomas correlated with histological types and grading. We also looked for a relationship between expression of apoptosis-related genes bcl-2, p53, c-myc and apoptosis meningiomas.

METHODS AND RESULTS

Fifty-one meningiomas of diverse histological subtypes and grades were investigated with in situ end-labelling of DNA fragments as well as immunohistochemical analysis of three apoptosis-related genes: p53, bcl-2 and c-myc. Our results showed that the apoptosis index was significantly higher in high-grade meningiomas (0.12%, n = 12) in than the benign meningiomas (0.023%, n = 39) P = 0.001) but there was no difference among the different histological subtypes of the benign meningiomas (P = 0.125). There is no obvious relationship between p53, bcl-2 and c-myc staining and apoptosis index in this group of meningiomas.

CONCLUSION

We conclude that apoptosis is an important phenomenon in meningiomas and that it is associated with atypical or malignant changes in meningiomas. Apoptosis in meningiomas has no clearcut relationship with expression of p53, bcl-2 and c-myc.

Prognostic significance of MIB-1, p53, and bcl-2 immunoreactivity in meningiomas

Sixty biopsy specimens of meningiomas, including 37 benign, 10 atypical, and 13 malignant meningiomas, were examined immunohistochemically using the monoclonal antibodies MIB-1 (a cell proliferation marker), p53, and bcl-2 (two apoptosis-associated markers). Benign meningiomas were subdivided into two groups: group 1, 29 tumors without recurrence; and group 2, eight tumors with recurrence after complete surgical resection. The mean MIB-1 labeling index (LI) values+/-SD were 1.3+/-3.2% for the benign, 9.3+/-6.9% for the atypical, and 15.0+/-16.9% for the anaplastic meningiomas. The mean MIB-1 LI+/-SD in group 1 tumors (n = 29) was 1.06+/-1.15%, and in group 2 tumors (n = 8), 2.3+/-4.76% (P = .028). p53 protein expression was found in 10.8% of the benign (10.34% of group 1 and 12.5% of group 2), 50% of the atypical, and 77% of the anaplastic meningiomas. bcl-2 protein expression was observed in 21.6% of the benign, 20% of the atypical, and 46.1% of the anaplastic meningiomas. Among the benign meningiomas, group 2 tumors expressed significantly more often bcl-2 protein (62.5%) than group 1 neoplasms (10.3%). Our results indicate that (1) in meningiomas, a good correlation exists between histological grading, MIB-1 and p53 protein expression, and (2) in benign meningiomas, the presence of bcl-2 protein expression together with high MIB-1 LI are associated with unfavorable prognosis of the disease.

Proliferation and DNA fragmentation in meningioma subtypes

Atypical meningioma has been introduced as tumour subtype of intermediate biological behaviour between classical and malignant meningiomas. To substantiate this three-step scale of malignancy, we assessed the proliferative activity reflected by Ki-67 (MIB1) labelling index (LI) in a series of 89 meningiomas, including 15 classical, 29 atypical, 35 anaplastic tumours, and 10 haemangiopericytomas and papillary meningiomas. The possible correlation of proliferation with the frequency of apoptosis and their relations to BCL-2 immunoexpression was investigated in seven classical, 10 atypical and 10 malignant meningiomas. Apoptosis was demonstrated by evaluation of the frequency of apoptotic figures, by the enzymatic technique of in situ tailing (IST) which stains apoptotic DNA fragments, and by DNA preparation and gel electrophoresis demonstrating DNA laddering in frozen tissues of five meningiomas. MIB1 LI revealed a highly significant increase from classical through atypical to anaplastic meningiomas (P < 0.0001); haemangiopericytomas and papillary meningiomas were well within the range of atypical meningiomas. IST indices rose with increasing malignancy and correlated with MIB1 LI (P < 0.0001): they showed a weak inverse correlation with BCL-2 immunoexpression (P = 0.05). BCL-2 expression tended to decrease with malignancy grade and was unrelated to MIB1 LI or frequency of apoptosis. Our data show that (i) apoptosis is a feature of meningiomas, significantly correlated with the malignancy scale. (ii) DNA fragmentation shows significant correlation with proliferation and inversely with BCL-2 expression; (iii) proliferation indices and frequencies of apoptosis/DNA fragmentation within meningioma subgroups corroborate the intermediate biological position of the atypical meningioma between classical and malignant meningiomas.

Meningioma grading: an analysis of histologic parameters

Histologic grading of meningiomas has prognostic and sometimes therapeutic implications, but diagnostic criteria for atypical meningioma are vague, and the significance of brain invasion in the determination of malignancy remains controversial. We reviewed our experience with 581 patients whose meningiomas were resected at Mayo Clinic during the years 1978 through 1988. All patients were followed until death or a median of 9.0 years. Ten histologic parameters were assessed and compared with recurrence-free survival. On univariate analysis, six variables were associated with recurrence, although most were statistically significant only in the subset of patients having undergone gross total tumor resection. On multivariate analyses, the most significant parameters were histologic brain invasion (when assessable) and maximal mitotic rate of at least four per 10 high-power fields (HPF). Also significant were combinations of at least three of the following four parameters: hypercellularity, architectural sheeting, macronucleoli, and small cell formation. Proposed grading criteria based on these findings yielded 81% classic, 15% atypical, and 4% brain invasive meningiomas with respective 5-year recurrence rates of 12%, 41%, and 56%. There was no association between histologic grade and either extent of surgical resection or patient age. However, male sex was associated with high-grade (atypical/brain invasive) tumors. Too few frankly anaplastic meningiomas were encountered for statistical analysis. Brain invasion and an increased mitotic index (at least four per 10 HPF) are the most powerful histologic factors prognostic for recurrence in meningiomas. We propose an objective definition for atypical meningioma based on our data. Because the difference in recurrence rates for brain invasive and atypical meningiomas was not statistically significant, it could not be determined whether brain invasion alone warrants a designation of malignancy. Likewise, we were unable to determine what constitutes histologic anaplasia due to the rarity of such cases.