Proliferative potential of brain tumors. Analyses with Ki-67 and anti-DNA polymerase alpha monoclonal antibodies, bromodeoxyuridine labeling, and nuclear organizer region counts

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.

Prognostic Factors in Adult Medulloblastoma. A Clinico-Pathologic Study

Aims and background.

Medulloblastoma in adults is a rare tumor. The small number of cases in the reported series has not permitted a definite assessment of the prognostic role of clinical, pathologic and cell kinetics factors. The largest series of medulloblastoma in adults treated in a single institution is herein reported.

Methods.

The clinical, therapeutic, pathologic and proliferation features of medulloblastoma in 44 adult patients (> 18 years) were analyzed retrospectively with regard to postoperative survival. The proliferation potential of each tumor was evaluated by the immunohistochemical demonstration of proliferating cell nuclear antigen (PCNA) and Ki-67, clone MIB-1, in paraffin sections.

Results.

The overall 5- and 10-year survival rates were 40% and 35.6%, respectively. Significant factors in predicting a longer postoperative survival were: age < 37 years, decade of management (1977-1990), radiotherapy (50-55 Gy on the posterior fossa and 30-35 Gy on the spinal cord) and nuclear isomorphism. When corrected for adequacy of radiotreatment, desmoplastic type and differentiation were significantly correlated with a shorter survival. The PCNA-labelling index (LI) ranged from 34.5 to 82.2%, the MIB-1-LI ranged from 9.6 to 64.7%. No association was found between PCNA- or MIB-1-LI values and microscopic features, or between LI values and prognosis.

Conclusions.

Contrary to a general assumption, desmoplastic medulloblastoma and differentiated medulloblastoma are negative prognostic factors in adequately radiotreated adult patients. This may possibly be referred to lower radiosensitivity of these tumor variants. The LI with PCNA or Ki-67 is of no help in identifying aggressive tumors.

Clinical Results of Unconventional Fractionation Radiotherapy in Central Nervous System Tumors

Malignant brain tumors (primary and metastatic) are apparently resistant to most therapeutic efforts. Several randomized trials have provided evidence supporting the efficacy of radiation therapy. Attempts at improving the results of external beam radiotherapy include altered fractionation, radiation sensitizers and concomitant chemotherapy. In low-grade gliomas, all clinical studies with radiotherapy have employed conventional dose fractionation regimens. In high-grade gliomas, hypofractionation schedules represent effective palliative regimens in poor prognosis subsets of patients; short-term survival in these patients has not allowed to evaluate late toxicity. In tumors arising within the central nervous system, hyperfractionated irradiation exploits the differences in repair capacity between tumour and late responding normal tissues. It may allow for higher total dose and may result in increased tumor cell kill. Accelerated radiotherapy may reduce the repopulation of tumor cells between fractions. It may potentially improve tumor control for a given dose level, provided that there is no increase in late normal tissue injury. In supratentorial malignant gliomas, superiority of accelerated hyperfractionated over conventionally fractionated schedules was observed in a randomized trial; however, the gain in survival was less than 6 months. At present no other randomized trial supports the preferential choice for altered fractionation irradiation. Also in pediatric brainstem tumors there are no data to confirm the routine use of hyperfractionated irradiation, and significant late sequelae have been reported in the few long-term survivors. Shorter treatment courses with accelerated hyperfractionated radiotherapy may represent a useful alternative to conventional irradiation for the palliation of brain metastases. Different considerations have been proposed to explain this gap between theory and clinical data. Patients included in dose/effect studies are not stratified by prognostic factors and other treatment-related parameters. This observation precludes any definite conclusion about the relative role of conventional and of altered fractionation. New approaches are currently in progress. More prolonged radiation treatments, up to higher total doses, could delay time to tumor progression and improve survival in good prognosis subsets of patients; altered fractionation may be an effective therapeutic tool to achieve this goal.

Advanced interstitial chemotherapy combined with targeted treatment of malignant glioma in rats by using drug-loaded nanofibrous membranes

Glioblastoma multiforme (GBM), the most prevalent and malignant form of a primary brain tumour, is resistant to chemotherapy. In this study, we concurrently loaded three chemotherapeutic agents [bis-chloroethylnitrosourea, irinotecan, and cisplatin; BIC] into 50:50 poly[(d,l)-lactide-co-glycolide] (PLGA) nanofibres and an antiangiogenic agent (combretastatin) into 75:25 PLGA nanofibres [BIC and combretastatin (BICC)/PLGA]. The BICC/PLGA nanofibrous membranes were surgically implanted onto the brain surfaces of healthy rats for conducting pharmacodynamic studies and onto C6 glioma-bearing rats for estimating the therapeutic efficacy.

The chemotherapeutic agents were rapidly released from the 50:50 PLGA nanofibres after implantation, followed by the release of combretastatin (approximately 2 weeks later) from the 75:25 PLGA nanofibres. All drug concentrations remained higher in brain tissues than in the blood for more than 8 weeks. The experimental results, including attenuated malignancy, retarded tumour growth, and prolonged survival in tumour-bearing rats, demonstrated the efficacy of the BICC/PLGA nanofibrous membranes. Furthermore, the efficacy of BIC/PLGA and BICC/PLGA nanofibrous membranes was compared. The BICC/PLGA nanofibrous membranes more efficiently retarded the tumour growth and attenuated the malignancy of C6 glioma-bearing rats. Moreover, the addition of combretastatin did not significantly change the drug release behaviour of the BIC/PLGA nanofibrous membranes. The present advanced and novel interstitial chemotherapy and targeted treatment provide a potential strategy and regimen for treating GBM.

Proliferative activity and apoptosis of Langerhans histiocytes in eosinophilic granulomas as evaluated by MIB-1 and TUNEL methods

Aims-To identify the role played by apoptosis in tumour regression.Methods-The growth fraction and apoptotic cell loss of four cases of eosinophilic granuloma were investigated using monoclonal antibodies against Ki-67 proliferation marker (MIB-1) antigen and the TdT mediated dUTP-biotin 3'-OH nick end labelling (TUNEL) method. These data were then compared with the clinical growth rate.Results-Only the Langerhans histiocytic cells, which reacted positively with anti-S-100 protein antibody, were immunolabelled with antibodies to proliferating cell nuclear antigen and Ki-67 antigen (MIB-1). Many apoptotic figures of histiocytic cells were also detected in all cases by the TUNEL method. In a patient whose tumour clinically showed spontaneous regression, the TUNEL staining index gave a higher score than the MIB-1 staining index.Conclusions-The main cause of the spontaneous regression of the tumours was postulated to be programmed cell death (apoptosis).

Age and bromodeoxyuridine labelling index as prognostic factors in high-grade gliomas treated with surgery and radiotherapy

AIMS

To determine the prognostic value of proliferative potential and DNA ploidy in 72 brain tumours (36 grade III and 36 grade IV astrocytomas) using bromodeoxyuridine (BrdUrd) incorporation and flow cytometry.

MATERIAL AND METHODS

All 72 patients underwent excision, mostly incomplete of the tumour. After surgery, eight patients received conventionally fractionated radiotherapy, 11 patients received accelerated radiotherapy, and 53 patients received hypofractionated radiotherapy. Tumour samples taken during surgery from each patient were incubated in vitro for 1 h at 37 degrees C with BrdUrd using the high pressure oxygen method. The percentage of BrdUrd-labelled cells (BrdUrd labelling index [BrdUrd LI]), and the total DNA content were evaluated:

RESULTS

The tumours showed variability in the BrdUrd LI values, which ranged from 0.3 to 19.1%. No difference was observed in mean BrdUrd LI between grade III and grade IV sub-groups. A significantly higher percentage of DNA aneuploidy was observed in grade III gliomas (69.4%) than in grade IV gliomas (52.8%). Univariate analysis showed that younger patients (< or = 51 years) (P = 0.021) with grade III gliomas (P = 0.030) and low tumour proliferation rate (BrdUrd LI < or = 2.7%, P = 0.028) had significantly higher 5-year survival rates. Tumour ploidy had no influence on patients' survival (P = 0.591). However, Cox multi-variate analysis showed that only age over 51 years, and high tumour proliferation rate (BrdUrd LI > 2.7%), were significant unfavourable prognostic factors in patient survival.

CONCLUSION

In this study, independent prognostic factors for patients with high-grade gliomas treated with surgery and post-operative radiotherapy are age and tumour proliferation rate assessed according to the BrdUrd LI.

Contralateral meningeal artery supply of paramedian meningiomas

BACKGROUND

When resecting at falcine or parasagittal portion of paramedian meningiomas, intraoperative hemostasis often is difficult despite effective management of ipsilateral meningeal arteries. We attribute such difficulties to meningeal artery blood supply from the contralateral side. We retrospectively studied feeding arteries from both sides in case of paramedian meningioma in terms of patient and tumor characteristics.

METHODS

Forty-three patients with paramedian meningiomas underwent selective internal and external carotid angiography. We investigated how contralateral meningeal arterial feeders related to patient profiles and imaging, histopathologic, and immunohistochemical findings.

RESULTS

Contralateral meningeal supply existed for 14 of 25 falcine meningiomas and 6 of 18 parasagittal meningiomas. Patients with contralateral feeders were 8.5 years younger than the others (P=.027) and were more likely to have larger tumors (P=.028). These were histopathologically malignant (P=.048), while showing more proliferation followed by monoclonal antibody against the Ki-67 antigen index (P=.012) and angiogenetic potential associated with vascular endothelial growth factor expression (P=.0085).

CONCLUSIONS

Contralateral meningeal supply may reflect strong angiogenetic recruitment from rapid tumor growth followed by high expression of vascular endothelial growth factor. This angiographical feature may predict the aggressive growth of paramedian meningiomas.

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.

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.

Radiotherapy and chemotherapy with or without carbogen and nicotinamide in inoperable biopsy-proven glioblastoma multiforme

BACKGROUND

Nicotinamide and carbogen have been shown to enhance the radiation effect in tumour models.

PURPOSE

Prospective evaluation of the toxicity and efficacy of carbogen and nicotinamide with external beam radiotherapy in the management of inoperable glioblastoma.

PATIENTS AND METHODS

From April 1995 to December 1997, 33 patients with inoperable biopsy-proven glioblastoma multiforme (GBM) were enrolled in a phase II trial, to undergo radiotherapy (59.4 Gy in 1.8 Gy/fraction), intra-arterial cerebral chemotherapy (ACNU 100 mg/m(2), three cycles), carbogen breathing (15 l/min), and nicotinamide (85 mg/kg). This experimental group was compared to a control group of 38 patients with inoperable GBM treated with radiotherapy and three cycles of nitrosourea-based chemotherapy from January 1990 to March 1995, in our institution.

RESULTS

In the experimental group, carbogen breathing was well tolerated, but only 51.5% of patients completed daily nicotinamide over the 6.5-week treatment period. Nausea and vomiting were the most frequent side effects of nicotinamide. No significant difference in overall survival was observed among the two treatment groups: median survival times were 36.7 and 35.3 weeks for patients treated with carbogen and nicotinamide, and for those treated in the control group, respectively.

CONCLUSION

The association of carbogen and nicotinamide with radiotherapy is feasible, but tolerable only in 51.5% of patients with GBM. Carbogen and nicotinamide did not appear to modify the evolution of glioblastoma.

Cytochemical and molecular biological aspects of the pituitary and pituitary adenomas--cell differentiation and transcription factors

The anterior pituitary is composed of several cell types, each responsible for the production of specific hormones. Each hormone secreting cells is defined by the activation of its respective hormone genes in a temporally and spatially regulated manner. Recent development in cytochemistry and molecular biology have provided various aspects of human pituitary adenomas, i.e., functional differentiation and classification. The molecular factors that determine hormone production have now been identified as transcription factors. Many novel transcription factors that play a role in anterior pituitary development are implicated. In this review, we focus on the transcriptional factors roles on functional differentiation of the pituitary cells and adenomas and the contribution of cytochemistry and recent development in molecular biological techniques.

Features of proliferation and in vitro drug resistance in central primitive neuro-ectodermal tumours

The features of proliferation in brain tumours are related with clinical prognosis for several types of brain tumours, especially gliomas. For childhood central primitive neuro-ectodermal tumours (cPNET), including medulloblastoma, this relation has previously been unclear. The aim of this study is to investigate the relationship between proliferative features of cPNET and in vitro resistance for cytostatic drugs measured with the 3-4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium-bromide (MTT) assay. Tumour material was obtained from 23 surgical specimens of cPNET. The expression of the proliferation markers Ki-67, proliferating cell nuclear antigen (PCNA) and cyclin D1 was determined with immunohistochemistry, while S-phase and DNA ploidy were analysed by flowcytometric analysis cell scan (FACS). The in vitro resistance for 10 cytostatic drugs was determined with the MTT assay. Drug resistance levels were available in 19 (83%) of the 23 samples with a complete profile of 10 cytostatic drugs tested in 14 samples. An excellent correlation in drug resistance scores was found between pharmacologically related drugs. The Ki-67 staining in 20 samples varied from 10 to 60% and from 30 to 100% for PCNA. Cyclin D1 staining was negative in 11 out of 18 samples. The S-phase in 16 samples ranged from 2 to 16%. Increased staining of Ki-67 was related with actinomycin D sensitivity (r -.603; P=0.022), while cells with a higher S-phase percentage were more resistant to ifosfamide (r.952; P<0.0001). In vitro drug resistance testing of central primitive neuro-ectodermal tumours (PNET) is feasible with the MTT assay. Ifosfamide resistance was related with increased Ki-67 and S-phase percentage of the tumour cells, while increased Ki-67 was also related with actinomycin D sensitivity. These findings suggest a cell cycle dependent activity of cytostatic drugs in vitro.

Calcified metastatic brain tumor--two case reports

A 29-year-old man and a 46-year-old woman presented with calcified brain metastasis from pulmonary adenocarcinoma. Both patients had a relatively benign clinical course and prolonged survival after total removal of the tumors. The male patient was still alive 2 years 3 months after surgical resection of the metastatic and primary tumors. The female patient had had brain metastasis 8 years after surgical resection of lung cancer, and survived for 3 years 3 months after removal of the brain metastasis. The MIB-1 indexes of the two cases were relatively low compared with other cases of brain metastases. Calcification and low MIB-1 index may indicate longer survival in patients with metastatic tumors if the primary tumor is controlled.

Enhanced apoptosis in pilocytic astrocytoma: a comparative study of apoptosis and proliferation in astrocytic tumors

Both cell proliferation and cell death occur simultaneously in tumor tissue, and extent of tumor growth reflects the net balance of these events. We correlated cell proliferation, spontaneous cell death, and alterations in tumor suppressor proteins with one another and with survival of patients with primary astrocytic tumors. In 39 astrocytic tumor specimens (6 pilocytic astrocytomas, 14 fibrillary astrocytomas, 9 anaplastic astrocytomas, and 10 glioblastomas), we determined the MIB-1 labeling index, the apoptotic ratio according to nick end labeling with morphologic confirmation, the p53 labeling index, and the presence of p53 or PTEN mutations. MIB- I labeling indices of pilocytic astrocytomas, fibrillary astrocytomas, anaplastic astrocytomas, and glioblastomas were 0.30+/-0.32; 1.84+/-1.87; 19.3+/-6.42; and 28.0+/-14.5 (mean +/- SD), respectively. Corresponding apoptotic ratios were 17.9+/-5.16; 3.96+/-3.57; 1.18+/-0.93; and 2.11+/-1.60 (mean +/- SD). The apoptotic ratio in pilocytic astrocytomas was significantly higher than in other astrocytic tumors (fibrillary astrocytomas, p < 0.05; anaplastic astrocytomas and glioblastomas, p < 0.01). MIB-1 showed a significant negative correlation with apoptosis (p < 0.01). MIB- I and apoptosis showed significant negative and positive correlations with patient survival (p < 0.01). Mutations of p53 and PTEN show no correlation with survival and apoptotic ratio. The apoptotic ratio can clearly distinguish pilocytic astrocytomas from other tumors, and this biological feature may reflect less aggressive growth of pilocytic astrocytomas.

PCNA and Ki-67 in central nervous system tumors: correlation with the histological type and grade

Determination of proteins in the control of proliferation in normal cells helps a better understanding of cellular transformation and proliferation mechanisms. Measurement of proliferative activity is important in determining the tumor grade, recurrence span and malignancy. Proliferating cell nuclear antigen (PCNA) and Ki-67 are two of the nuclear markers used to demonstrate the proliferative phase of the cell cycle. In the present study, 63 central nervous system (CNS) tumors of various histologic types, diagnosed in Cukurova University Medical Faculty. Department of Pathology and graded according to WHO grading system were examined for PCNA and Ki-67 monoclonal antibodies using immunohistochemistry. Results were analyzed with statistical methods. Distribution of PCNA and Ki-67 LI (labeling index) values were determined for different tumor types. The highest PCNA and Ki-67 LI values were detected in medulloblastoma, malignant meningioma, primitive neuroectodermal tumor (PNET) and glioblastoma (GBM) groups, while pilocytic astrocytoma, meningioma, craniopharyngioma and oligodendroglioma showed the lowest values. In such tumors, the correlation between the increasing grade and PCNA and Ki-67 LI values were statistically significant. A correlation between the clinical outcome and Ki-67 and PCNA LI values was also detected. Conclusively, both markers can be used to evaluate the tumor grade and to asses the possibility of recurrence and malignancy in CNS tumors.

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.

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).

Accelerated radiotherapy, carbogen, and nicotinamide in glioblastoma multiforme: report of European Organization for Research and Treatment of Cancer trial 22933

PURPOSE

A three-step phase I/II trial associating accelerated radiotherapy with carbogen (step 1, ARCO), with nicotinamide (step 2, ARN), or with both (step 3, ARCON) was conducted, the aim of which was to overcome the effects of proliferation and hypoxia as potential causes of tumor radioresistance in glioblastoma multiforme.

PATIENTS AND METHODS

Radiotherapy consisted of 60 Gy delivered over 4 weeks in 1.5-Gy fractions twice daily, 5 days a week. Carbogen breathing was started 5 minutes before each fraction and continued until the end of each treatment session. Nicotinamide was given daily as a single oral dose of 85 mg/kg.

RESULTS

A total of 115 patients with a median age of 55 years were registered. Of 107 eligible patients, 23 were registered in step 1, 28 in step 2, and 56 in step 3. The planned treatment was administered without any interruption in 72% of patients (86% in ARCO but 68% in ARN and ARCON). The incidence and severity of acute skin and mucous membrane toxicity were higher in patients who received nicotinamide (ie, the ARN and ARCON groups). Grade 1 to 2 gastrointestinal toxicity was observed in 44% of patients in the ARN group and 32% of patients in the ARCON group, but only in 8% of patients in the ARCO group. Eight percent of evaluated patients presented with abnormal liver test results at treatment completion. The dose of corticosteroids had to be increased in 44% of patients. Late neurologic side effects were similar in all treatment steps and were observed mostly in patients with disease progression. Median survival times for patients treated with ARCO, ARN, and ARCON were 10.1, 9.7, and 11.1 months, respectively.

CONCLUSION

Feasibility of ARCO treatment was good but that of ARN and ARCON was only fair. This probably reflected the higher acute toxicity rate, particularly gastrointestinal, for patients receiving nicotinamide. The dose of corticosteroids had to be increased frequently during treatment, suggesting a higher than expected acute neurologic toxicity. Overall survival was similar in the three treatment steps and not different when compared with results of other series that used radiotherapy alone.

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.

Clinical presentation, diagnosis, and pharmacotherapy of patients with primary brain tumors

OBJECTIVE

To briefly review the clinical presentation and diagnosis of patients with primary brain tumors, followed by an in-depth survey of the pertinent pharmacotherapy.

DATA SOURCES

A detailed search of the neurologic, neurosurgical, and oncologic literature for basic science research, clinical studies, and review articles related to chemotherapy and pharmacotherapy of primary brain tumors.

STUDY SELECTION

Relevant studies on tissue culture systems, animals, and humans examining the mechanisms of action, pharmacokinetics, clinical pharmacology, and treatment results of chemotherapeutic agents for primary brain tumors. In addition, studies of pharmacologic agents administered for supportive care and symptom control are reviewed.

DATA SYNTHESIS

Primary brain tumors derive from cells within the intracranial cavity and generally present with headache, seizure activity, cognitive changes, and weakness. They are diagnosed most efficiently with magnetic resonance imaging. After diagnosis, the most common supportive medications include corticosteroids, gastric acid inhibitors, and anticonvulsants. Chemotherapy is adjunctive treatment for patients with malignant tumors and selected recurrent or progressive benign neoplasms. In general, the most effective chemotherapeutic drugs are alkylating agents such as the nitrosoureas, procarbazine, cisplatin, and carboplatin. Other agents used include cyclophosphamide, methotrexate, vincristine, and etoposide. Angiogenesis inhibitors and gene therapy comprise some of the novel therapeutic strategies under investigation.

CONCLUSIONS

The efficacy of chemotherapy for primary brain tumors remains modest. Novel agents must be discovered that are more specific and attack tumor cells at the molecular level of tumorigenesis. Furthermore, strategies must be developed to counteract the pervasive problem of brain tumor chemoresistance.

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.

Ki-67 (clone MIB-1) proliferation index in recurrent glial neoplasms: no prognostic significance

BACKGROUND

To determine if the Ki-67 (MIB-1 clone) proliferative index (PI) has prognostic potential in patients with recurrent astroglial neoplasms.

METHODS

We conducted a retrospective review of 27 patients whose initial and recurrent specimens were available. Histopathology was determined according to the World Health Organization classification. Proliferation index was calculated on formalin-fixed tissue using the Ki-67 (MIB-1 clone) antibody. Morphometric data were analyzed in conjunction with clinical data and Cox Proportionate Hazards Analysis, Spearman's correlation coefficient and Mann-Whitney Test.

RESULTS

Initial histopathology included 14 glioblastoma multiforme, 7 anaplastic astrocytoma, 3 oligoastrocytoma, and 3 astrocytoma. Recurrent specimens showed changes consistent with treatment. While univariate analysis shows initial histology correlated with survival (p<0.036), PI did not correlate with survival after either initial (p = 0.86) or recurrent (p = 0.46) surgery for any tumor type. PI difference between specimens also did not correlate with survival (p = 0.91). Initial PI did not correlate with recurrent PI either (p = 0.43).

CONCLUSIONS

Ki-67 PI does not confer additional prognostic information for patients with recurrent astroglial neoplasms. One possible explanation for this observation is that treatment may alter the PI independent of its effect on tumor growth.

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.

The role of Ki67 proliferation assessment in predicting local control in bladder cancer patients treated by radical radiation therapy

PURPOSE

To assess whether tumour proliferation as measured by Ki67 immunostaining has any predictive value for local control in bladder cancer patients treated by radiotherapy.

PATIENTS AND METHODS

Fifty-five patients suffering from infiltrating bladder carcinoma recommended for radical radiotherapy (66 Gy/6-7 weeks) were included in this study. Paraffin-embedded pre-treatment tumour sections were stained with the Ki67 antibody. The percentage of Ki67-positive nuclei was correlated with established prognostic factors, local control and survival.

RESULTS

The Ki67 index was not related to local control in our patients when the median was selected as the cut-off value. Patients with tumours with a very low (<27%) Ki67 index had better local control at 5 years (69%) than patients with tumours with greater (>27%) Ki67 expression indices (31.5%) (P<0.05; log-rank test).

CONCLUSIONS

Ki67 immunostaining was a feasible method to estimate tumour proliferation. Patients with very low proliferating tumours seemed to achieve better local control after fractionated radiotherapy compared to other patients. Further studies are needed with a greater number of patients to accurately define the role of Ki67 expression in predicting tumour repopulation during fractionated radiotherapy.

Ependymomas: MIB-1 proliferation index and survival

The biologic behavior of ependymomas is highly variable, and its correlation with histologic features is at best imprecise. This retrospective study attempted to correlate the malignant histologic characteristics of ependymomas with MIB-1 proliferation index and survival. Biopsy and resection specimens taken from 34 patients who received treatment 1972 to 1996 were histologically examined. The patients' ages range was 1 to 59 years. The histologic specimens were assessed for anaplastic features (necrosis, mitosis, vascular proliferation, cellular pleomorphism, and overlapping of nuclei) and an MIB-1 (Ki-67 antigen) proliferation index was also determined. The overall median MIB-1 proliferation index was 7.8% (range 0.1 - 62.5%). An MIB-1 of 20% was significant for a decrease in survival (RR = 5.7) (p = 0.0013). The median MIB-1 for patients < 20 years old was 20.6% with range (0.1, 43%), while that for patients > 20 years was 5.1% (range 0.2, 9.4%) (KW p = 0.055). Three of 5 histological features evaluated were significantly associated with outcome: > 5 mitotic figures per high-power field, necrosis, and vascular proliferation, but not nuclear overlap or pleomorphism. All pathologic factors except pleomorphism were significantly related to the MIB-1 proliferation index. In brief, our data support the association of poor prognoses in ependymomas with young age, the presence of three to four anaplastic histologic features, and an MIB-1 proliferation index > 20%.

MIB-1 labeling index in nonpilocytic astrocytoma of childhood: a study of 101 cases

BACKGROUND

The prognosis of pediatric patients with nonpilocytic astrocytoma, and in particular those with anaplastic astrocytoma, is somewhat unpredictable. This study used MIB-1 monoclonal antibody, a proliferative marker that can be used in formalin fixed paraffin embedded tissues, to study nonpilocytic pediatric astrocytoma.

METHODS

Astrocytoma, anaplastic astrocytoma, and glioblastoma specimens excised from a total of 101 pediatric patients during the period from January 1975 to September 1996 were retrieved from the authors' surgical pathology file. Histologic grading of the specimens was performed based on a modified Ringertz system. The proliferative potential of the tumors was estimated by using the MIB-1 labeling index (LI), which was evaluated with morphologic grades of tumors and survival of the patients.

RESULTS

Of the 101 patients, 34 had astrocytoma, 33 had anaplastic astrocytoma, and 34 had glioblastoma. Their mean survival times were 165.2+/-14.9 months (mean+/-standard error; SE), 46.1+/-9.9 months, and 21.8+/-5.6 months, respectively. The mean MIB-1 LI of different tumor grades were as follows: astrocytoma, 3.9+/-4.3 (mean+/-standard deviation; range, 0.0-21.6); anaplastic astrocytoma, 24.3+/-15.6 (range, 1.7-62.8); and glioblastoma, 35.9+/-16.4 (range, 7.36-63.3). The mean survival of the entire group of patients with LIs < or = 11 was 173.2+/-12.2 months (mean+/-SE), and the mean survival of those with LIs > 11 was 20.3+/-4.1 months. The survival of anaplastic astrocytoma patients with LIs < or = 11 was similar to that of astrocytoma patients, whereas the survival of anaplastic astrocytoma patients with LI > 11 was similar to that of patients with glioblastoma.

CONCLUSIONS

The results of the current study show that histopathologic grading can predict the outcome for patients with astrocytomas and glioblastomas, whereas MIB-1 LI can separate better and worse prognostic groups in patients with anaplastic astrocytoma.

Significance of cell proliferation measurement in gastric cancer

Cell kinetic data may be important indicators of clinical behaviour in many types of cancer. Recently, several antibodies to cell-cycle associated antigens have been characterised. This overview summarises the advantages and disadvantages of different methods for the assessment of cell proliferation. Moreover, the prognostic value of proliferative activity in gastric cancer is discussed and suggestions for future research are given.

Is medulloblastoma the same tumor in children and adults?

The appearance of medulloblastoma in adult age and the uncertain overlapping of prognostic factors in pediatric and adult populations stimulate the question of whether medulloblastoma is different in adults and in children. The pathologic features, proliferation potential and glial/neuronal differentiation have been investigated in 42 adult medulloblastomas and 42 medulloblastomas of children; the quantitative data have been compared between the two groups of age. Homer-Wright rosettes, nuclear polymorphism and histologic signs of neuronal differentiation were more frequent in children cases; GFAP-positive tumor cells and desmoplastic type were more frequent in adult cases. The mean, median and rage of Lis, with PCNA and MIB-1 were significantly (p < 0.05) higher in adults than in children. All cases, independently from age of the patients were immunoreactive with markers of neuronal commitment (class III beta tubulin isotype, MAP-2, neurofilaments). The immunoreactivity pattern suggested a more mature neuronal character in desmoplastic cases of adults than of children and in classic cases of children than of adults. In conclusion, some phenotypic differences between childhood and adult medulloblastoma exist, but do not support a substantially different course of the disease. The higher proliferation potential in adult than in childhood cases is unexpected in a tumor of embryonal origin, and reduces the applicability of Collin's law to medulloblastoma.

Diagnostic importance of the nucleolar organizer regions in Wegener's granulomatosis

The number and distribution pattern of silver staining nucleolar organizer regions (AgNORs) were thought to reflect the cellular proliferative activity and the malignancy of tumours. Using a silver-staining method, the variations of AgNORs have been studied in patients with atypical inflammatory lesion (n = 5), malignant reticulosis (n = 5) and Wegener's granulomatosis (n = 6). Our results reveal that there was a statistically significant difference (p < 0.01), highly suggestive of a difference in AgNOR counts between the atypical inflammatory lesion and Wegener's granulomatosis, with the Wegener's granulomatosis specimens having the higher irregular AgNORs, but the difference between Wegener's granulomatosis and malignant reticulosis is probably not clinically important. It is concluded that AgNORs may be useful in differentiating Wegener's granulomatosis from an atypical inflammatory lesion, and the simplified counting technique is adequate for the purpose.

Immunohistochemical examination of proliferative potentials and the expression of cell cycle-related proteins of intracranial chordomas

The difference in biological features between recurrent and nonrecurrent intracranial chordomas has not been studied. In this study, proliferative potentials of chordomas were studied with an immunohistochemical staining method, mainly using anti-Ki-67 antibody, MIB-1, which is known to be available for archival paraffin sections, together with immunohistochemical studies on the expression of cell cycle or apoptosis-related proteins, including p53, cyclin D1, and bcl-2 proteins. The correlation among MIB-1 staining indices, the immunoreactivities of these proteins, and clinical courses of intracranial chordomas were analyzed retrospectively, and the statistically significant correlation between MIB-1 staining index (SI) and recurrence has been clarified. The mean MIB-1 SI of recurrent tumors was 10.2%, being shown to be higher than that of nonrecurrent tumors (2.8%). The immunohistochemically positive staining of cell cycle-related protein, especially p53 and cyclin D1 proteins, correlated well with recurrence and high MIB-1 SI. In conclusion, both the examination of proliferative potentials of chordomas using MIB-1 SI and the study of the immunoreactivity of p53 and cyclin D1 proteins are important for their biological and histopathological analyses and the prediction of future recurrence.

Hyperfractionated and accelerated radiation therapy in central nervous system tumors (malignant gliomas, pediatric tumors, and brain metastases)

The authors review the main contributions of the international literature concerning the role of hyperfractionation (HF), accelerated fractionation (AF), and accelerated hyperfractionation (AHF) of the dose in radiation therapy (RT) of central nervous system tumors. Basic rationales, clinical results, acute/late toxicity, and current prospectives are summarized in three sections focusing on malignant gliomas, pediatric brainstem tumors, and brain metastases. In supratentorial malignant gliomas the superiority of AHF (0.89 Gy x 3 fractions/day; total dose 61.4 Gy) over conventional fractionation ((CF) total dose 58 Gy) was demonstrated by a randomized trial. However, the gain in median survival time was less than 6 months. No other randomized trials support the preferential choice of non-CF schedules outside clinical trials. Ongoing trials are exploring the role of AHF in combination with chemotherapy, hypoxic cell and radiosensitizing agents. As for pediatric brainstem tumors, there are no data to support the routine use of HF that should be preferably used in an investigative setting. As late sequelae have been reported in the few long-term survivors, patients should be carefully selected. Regarding brain metastases AF RT and AHF RT, with their faster treatment course, may represent a convenient alternative to CF RT for the palliation of brain metastases. In carefully selected patients with solitary brain metastases non-CF RT may be part of aggressive treatment approaches.

Cell proliferation and p53 protein expressions in cutaneous epithelial neoplasms

We investigated correlations between cell proliferation, p53 overexpression, and degree of malignancy in cutaneous epithelial neoplasms. One hundred and fourteen cases of epithelial neoplasms, including seborrheic keratosis (SEB), basal cell carcinomas (BCCs), solar keratosis (SK), Bowen's disease (BD), and squamous cell carcinomas (SCCs) were examined using argyrophilic nucleolar organizer region (AgNOR) staining. In addition, immunohistochemical analysis using the Ki-67 (MIB-1) and anti-p53 (DO-7) monoclonal antibodies was performed. The ratio of tumorous to normal cells according to AgNOR staining was defined as the AgNOR rate, and the ratio of tumorous to normal cells according to Ki-67 recognition was defined as the Ki-67 rate. SCC lesions showed the highest AgNOR rate among the investigated epithelial neoplasms, followed in order by BD, BCC, SK, and SEB lesions. The Ki-67 rate was highest in BD lesions, followed in order by SK, SCC, BCC, and SEB lesions. Expression of p53 protein was highest in SK lesions. SCC is generally considered to be the most malignant neoplasm, followed in order by BCC, BD, and SK. Thus, our results suggest that the Ki-67 rate and overexpression of p53 protein do not always reflect the degree of malignancy in neoplasms.

Histopathology of post-embolized meningiomas

Although embolization of meningiomas has been performed for many years as a preoperative adjunct to reduce tumor vascularity and facilitate surgical excision, little has been written about the features of the histological artefacts introduced by the process. In particular, the fact that it may produce tumor necrosis may potentially cause confusion with atypical or malignant meningiomas. In this study, 25 meningeal tumors of different histological subtypes, all of which had been previously embolized, were reviewed histologically as well as with immunostaining for the MIBI antigen and proliferating cell nuclear antigen (PCNA). Necrosis, in the form of confluent necrosis as well as micronecrosis, was the most common feature (48%). Other characteristic features included florid ischemic changes (16%), intravascular Ivalon particles (24%), and fibrinoid necrosis of vascular walls (12%). Histological changes showed no obvious relationship with the interval between embolization and surgery. There was an increase in MIB1 and PCNA labelling indices in those tumor exhibiting necrotic foci, but it did not seem to have any prognostic significance. We believe pathologists should be familiar with the histological changes induced by embolization in meningiomas so that an erroneous diagnosis of a high-grade lesion will not be made.

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

Meningiomas from 40 adult patients were labeled immunohistochemically with monoclonal antibodies to bromodeoxyuridine (BUdR) and the Ki-67 antigen, MIB-1. The meningiomas were classified as classical, or benign (n = 31); atypical (n = 4); or malignant (n = 5). Meningeal sarcomas and hemangiopericytomas were excluded. The patient population consisted of 26 women and 14 men, ranging in age from 26 to 75 years. BUdR proliferation indices ranged from 0% to 5.8%, measurements that were expectedly lower than those for MIB-1, which ranged from 1.5% to 19.3%. MIB-1 proliferation indices were not significantly affected regarding steroid pretreatment or age. These results show a good correlation between the BUdR and MIB-1 proliferation markers (rs = 0.72; P < .0001), which supports the use of anti-MIB-1 as an alternative labeling tool to BUdR for the determination of the proliferation index in meningiomas, thus avoiding the administration of a potentially mutagenic drug.

Prognostic significance of Ki-67 labeling indices obtained using MIB-1 monoclonal antibody in patients with supratentorial astrocytomas

BACKGROUND

Identification of the prognosis of patients with gliomas is important for selecting and evaluating the effectiveness of treatment. The aim of this study was to evaluate the Ki-67 labeling index (LI) using the newly generated MIB-1 monoclonal antibody (MoAb) as a prognostic indicator for patients with astrocytomas.

METHODS

Ki-67 immunohistochemistry was performed on paraffin sections to estimate the growth potential of 72 supratentorial astrocytomas using the MIB-1 MoAb after hydrated autoclaving treatment. Multivariate analysis using the Cox proportional hazard stepwise model was used to evaluate the influence of Ki-67 LI, as well as other prognostic factors, on the duration of survival of patients with supratentorial astrocytomas.

RESULTS

The mean Ki-67 LI was 3.8% (+/- 2.7%; standard deviation [SD]) in Grade 2 gliomas (n = 19), 18.4% (+/- 9.7% SD) in Grade 3 gliomas (n = 25), and 31.6% (+/- 12.9% SD) in Grade 4 gliomas (n = 28). Multivariate survival analysis showed that histologic grade, Ki-67 LI, and Karnofsky performance status (KPS) score before and after treatment were independent, statistically significant prognostic factors for patients with all grades of astrocytomas. In high grade lesions, Ki-67 LI, tumor location (superficial vs. deep), and KPS score after treatment were significant prognostic variables, whereas histologic grade did not meet the significance level for entry into the stepwise model.

CONCLUSIONS

These results indicate that the Ki-67 LI obtained using MIB-1 MoAb is an important and practical tool for estimating biologic behavior of gliomas, as well as for predicting survival.

Meningioma: proliferating potential and clinicoradiological features

We examined the proliferative potentials of meningiomas in 120 patients using the MIB-1 antibody against the Ki-67 antigen and compared them with the clinicoradiological features. The Ki-67 staining index (SI) did not relate to the age and sex of the patients or the location of the tumors. Asymptomatic meningiomas showed significantly lower SIs (mean +/- standard deviation [SD], 0.87 +/- 0.56%) than symptomatic meningiomas (mean +/- SD, 1.63 +/- 2.17%). We found no relation between SIs and clinical symptoms and signs in the symptomatic meningiomas. A weak correlation was found between the size of tumors and Ki-67 SIs (r = 0.21; P = 0.024). There were significant differences in SIs between calcified (mean +/- SD, 0.77 +/- 0.41%) and noncalcified tumor (mean +/- SD, 1.75 +/- 2.25%). Diffusely calcified tumors (mean +/- SD, 0.57 +/- 0.34%) showed lower SIs than focally calcified tumors (mean +/- SD, 0.92 +/- 0.41%). Lobulated tumors showed higher SIs (mean +/- SD, 2.85 +/- 3.68%) than round tumors (mean +/- SD, 1.06 +/- 0.67%). Tumors with perifocal edema or unclear borders had higher SIs than did those without such features. Signal intensities on T1-weighted magnetic resonance images had no relation to SIs, whereas low-intensity tumors on T2-weighted images, most of which presented diffuse calcification on computed tomographic scans, showed lower SIs. This study indicates that several clinicoradiological features relate to the proliferative potential of meningiomas and that they may contribute to the management of patients.

Proliferating cell nuclear antigen and Ki-67 immunohistochemistry of oligodendrogliomas with special reference to prognosis

BACKGROUND

The biologic behavior of oligodendrogliomas is somewhat unpredictable. A supplementary prognostic factor is, therefore, desirable.

METHODS

Thirty-two pure supratentorial oligodendrogliomas were investigated using proliferating cell nuclear antigen (PCNA) and Ki-67 immunohistochemical analyses. The correlation of PCNA and Ki-67 labeling index (LI) with prognosis were studied, and the correlation of LI with clinical data was evaluated.

RESULTS

The PCNA LI had a range of 0-17% (mean, 5.27%; standard deviation [SD] = 4.65), and the Ki-67 LI had a range of 0-29% (mean, 4.19%; SD = 5.66). In general, the PCNA LI seemed to be higher than the Ki-67 LI. The mean survival time was 4.4 years, and 5- and 10-year survival rates were 38% and 19%, respectively. Ki-67 and PCNA staining indicated that patients with a high LI (> 3% and > 4%, respectively) had a significantly higher mortality, with mean survival time of 23.5 months and 26.2 months, respectively. No significant correlation between LI (or survival) and tumor size, cerebral localization, radiation, resection/biopsy, sex, age, or cytologic atypia was found.

CONCLUSIONS

The use of Ki-67 and PCNA LI higher than 3% and 4%, respectively, appears reliable as prognostic factors when investigating pure supratentorial oligodendrogliomas.

Intracranial meningioma masquerading as a primary pleuropulmonary tumor

Extracranial metastasis was found in an intracranial meningioma with low proliferative potential before the detection of the primary tumor. Pleuropulmonary tumors were incidentally detected on chest X-ray in an asymptomatic 25 year old female. Excised tumors of the right pleura and lung showed histological features similar to meningotheliomatous meningioma, which led to the discovery and excision of the intracranial tumor. Both tumors showed the same histologic pattern: meningotheliomatous meningioma with low mitotic activity. The proliferative component, determined by the monoclonal antibody Ki-67, was further evaluated in the primary tumor and the metastases of the present case, as well as in 12 other intracranial meningiomas. Ki-67 positive ratios at the primary and metastatic sites of the present cases were 1.2 and 1.1%, respectively, which is as low as other benign meningiomas, and this suggests that factors other than the proliferative potential is responsible for extracranial metastasis of meningioma.

Expression of the small heat shock protein (hsp) 27 in human astrocytomas correlates with histologic grades and tumor growth fractions

1. Cellular expression and distribution of the stress response small heat shock protein 27 (hsp27) in 39 high-grade astrocytomas (27 glioblastoma multiformes, 12 anaplastic astrocytomas) and in 27 low-grade astrocytomas (grade I-II) were analyzed immunohistochemically. 2. The correlation between hsp27 expression and tumor growth fractions of the astrocytomas was examined following Ki-67 immunostaining. 3. The hsp27 staining was cell cytoplasmic. The hsp27 immunopositive rate was significantly higher in high-grade astrocytomas; the rates was 74% for glioblastomas, 58% for anaplastic astrocytomas, and 37% for low-grade astrocytomas. The small and large tumor cells, especially in glioblastomas, multinucleated tumor giant cells, tumor cells in the pseudopalisading and necrotic areas, cells of the microvascular endothelial proliferations, and tumor vascular smooth muscles were usually hsp27 positive. The mean percentage of hsp27-positive cells was significantly higher in the glioblastomas alone and in the combined high-grade astrocytomas, compared to the low-grade, and in recurrent rather than in primary high-grade astrocytomas. 4. The high-grade astrocytomas had a highly statistical significant Ki-67 labeling index. The Ki-67 labeling indices were significantly higher in the hsp27-positive than the hsp27-negative astrocytomas, irrespective of the histological grade. In the high-grade astrocytomas with a Ki-67 labeling index of five and above, 81% of those tumors were hsp27 positive. 5. Thus, a large number of human astrocytomas express hsp27, and hsp27 expression correlates with histological grades of astrocytoma and with tumor growth fractions. This being the case, hsp27 is likely to have a role in the growth of human astrocytomas.

The comparison between the growth fraction of bilateral vestibular schwannomas in neurofibromatosis 2 (NF2) and unilateral vestibular schwannomas using the monoclonal antibody MIB 1

Formalin-fixed paraffin sections of 55 consecutive bilateral vestibular schwannomas in 46 patients with neurofibromatosis 2 (NF2), and 50 patients with unilateral vestibular schwannomas were investigated immunohistochemically with the monoclonal antibody MIB 1 directed against recombinant parts of Ki-67 antigen. The immunohistochemical staining was carried out on dewaxed microwave oven-processed paraffin sections of formalin-fixed tumour tissues. The labelling index (LI) obtained was compared to clinical and histological findings in both groups. There was no correlation between the LI and age of the patients, tumour size, or histological type of tumour (Antoni A or B). Vestibular schwannomas in NF2 showed higher LI than unilateral vestibular schwannomas: the maximal LI found per section (LI max) ranged from 0.4 to 17.6% (mean, 2.7%) in NF2 schwannomas, and from 0 to 9% (mean, 2.2%) in unilateral schwannomas. These differences may express immunohistochemically some clinical and morphological differences between bilateral and unilateral vestibular schwannomas.