Expression of extracellular matrix-degrading proteins in classic, atypical, and anaplastic meningiomas

Although the majority of meningiomas, commonly benign tumors (WHO I), are amenable to surgical resection, a percentage of up to 3% will recur as higher-grade meningiomas with potential brain invasion. Our study aims at the in situ identification of proteolytic, extracellular matrix-degrading enzymes in a broad spectrum of meningiomas. We examined 80 meningiomas (50 classic meningiomas WHO I, 19 meningiomas WHO II, including atypical, chordoid, and clear cell types, as well as 11 anaplastic meningiomas WHO III) for the immunohistochemical expression patterns of cathepsin D and metalloproteinases MMP-2 and MMP-9. Meningiomas of all types and grades revealed a distinct expression of MMP-9 and cathepsin D, while MMP-2 was found predominantly in WHO II and III meningiomas. There was a significant increase in positive tumor cells from WHO grade I to II and III for MMP-2 (p<0.001), but not for cathepsin D (p=0.099). MMP-9 displayed an increased number of positive tumor cells from WHO grade I to II, but a decrease in WHO III meningiomas (p<0.002). Routine screening for the expression of metalloproteinases and cathepsin D will not reveal any new diagnostically or prognostically relevant information. However, these factors may represent a potential target for pharmacological blocking as an anti-invasive therapy.     

Osteopontin predicts the behaviour of atypical meningioma

Lin C‐K, Tsai W‐C, Lin Y‐C & Hueng D‐Y
(2012) Histopathology  60, 320–325
Osteopontin predicts the behaviour of atypical meningioma Aim: Although the World Health Organization (WHO) histological criteria distinguishing benign from atypical and malignant meningioma are clear, discerning benign from atypical meningioma is still somewhat difficult, leading to interobserver diagnostic variability. Osteopontin (OPN) and cortactin play important roles in tumorigenesis, invasion and metastasis of several human cancers. The aim of this study was to evaluate the usefulness of OPN and cortactin immunohistochemistry for distinguishing between benign, atypical and malignant meningioma and predicting their recurrence. Methods and results: Seventy‐five specimens (48 benign, 17 atypical and 10 malignant meningiomas) were investigated immunohistochemically. The mean immunohistochemical scoreimmunohistochemical score ± SE of the mean of both OPN and cortactin were significantly higher in grade II or grade III meningiomas than in grade I meningioma. Discriminant analysis of immunohistochemical OPN expression showed correct classification of 97.7% of WHO grade I meningiomas and 88.2% of WHO grade II meningiomas (95.4% accuracy). However, the same analysis of cortactin expression showed correct classification of 95.8% of WHO grade I meningiomas and only 23.5% of WHO grade II meningiomas (76.9% accuracy). A cut‐off for predicting grades I and II meningioma recurrence was determined for OPN (3.0) but not for cortactin. Finally, logistic regression identified both this cut‐off (P < 0.05) and WHO grade (P < 0.05) as independent risk factors for recurrence. Conclusions: OPN expression is a valuable marker for diagnosis of atypical meningioma and prediction of grades I and II meningioma recurrence.     

Correlation of p63 protein expression with histological grade of meningiomas: an immunohistochemical study

Prediction of tumor behavior in meningiomas based on morphological features alone remains difficult. Several immunohistochemical biomarkers have been proposed to assist conventional methods. However, no single immunohistochemical marker can unequivocally discriminate between benign and aggressive meningiomas. There is only 1 study available in the literature that correlates p63 expression with overall histological grade of the meningioma. The present study is undertaken to assess the correlation between p63 expression and histological grade of meningiomas. For this purpose, the authors studied and analyzed the immunohistochemical expression of p63 in 85 cases of meningioma, including WHO grade I (63), grade II (11), and grade III (11) cases. Correlation between histological grade and nuclear immunoreactivity to p63 antibody was performed. Furthermore, expression of p63 protein was correlated with short clinical follow-up and Ki-67 proliferation index. Among 85 patients analyzed, there were 61 women (71.7 %) and 24 men (28.2%) between 7 and 75 years old. Expression of p63 protein was found in 34.9% of grade I cases, but in grade II and III, 63.6% of cases each were immunoreactive. Correlation between histological grade and p63 immunoreactivity was significant (P = .02). p63-positive grade I meningiomas did not show elevated Ki-67 index. The present study contradicts earlier reports because there are a considerable number of grade I meningiomas that express p63. Although p63 expression is significantly associated with higher histological grade of meningiomas, it may not be considered as a sole biomarker to assess aggressive behavior of the tumor.     

Cyclooxygenase-2 (COX-2) overexpression in meningiomas: real time PCR and immunohistochemistry.

Cyclooxygenase-2 (COX-2) is the inducible form of the enzyme involved in the first steps of the prostaglandins and thromboxane synthesis. COX-2 up-regulation is demonstrated in tumors where it can modulate tumoral progression, metastasis, multidrug resistance, and angiogenesis. Experimental data suggest a possible therapeutic use of the COX-inhibitors nonsteroidal antiinflammatory drugs (NSAIDs). NSAIDs can block tumor growth through many mechanisms, especially through antiangiogenic and proapoptotic effects. Moreover, NSAIDs can also improve the efficacy of radiotherapy, chemotherapy, and hormonal therapy. This study reviews the COX-2 expression as evaluated through immunohistochemistry and real time polymerase chain reaction (RT-PCR) in 23 meningiomas [14 World Health Organization (WHO) grade I; 5 WHO grade II; 3 WHO grade III; 1 oncocytic meningioma]. At immunohistochemistry all the lesions but 4 (83%) were COX-2 positive. At RT-PCR 9 meningiomas, 8 WHO grade I and 1 WHO grade II, showed a COX-2 expression greater than the reference value (average expression of all meningiomas that we studied). The association between tumor grade and immunohistochemical or RT-PCR COX-2 expression was not significant (P=0.427 and P=0.251, respectively). In conclusion, even if further studies on larger series are necessary, the common COX-2 overexpression in meningiomas may suggest considering the COX-2 inhibitors, alone or in combination with radiotherapy, a potential area of therapeutic intervention in some selected meningiomas.     

Cathepsin D as a potential prognostic marker for lung adenocarcinoma

We previously identified cathepsin D as a possible marker for lung adenocarcinoma (AD). The purpose of the present study is to evaluate the correlation between cathepsin D expression and clinicopathological findings or prognosis. We conducted immunohistochemistry (IHC) to assess 150 AD tissues. For these 150 tumors, TTF-1 expression, EGFR and KRAS gene mutations, and ALK rearrangements had already been examined. Cathepsin D expression was detected in 44% (66 of 150, IHC score ≥1+) and 27.3% (41 of 150, IHC score ≥2+). Cathepsin D-positive (IHC score ≥2+) tumors were more poorly differentiated than cathepsin D-negative ones, while all lepidic predominant invasive adenocarcinomas showed no cathepsin D expression. Univariate analysis revealed a poor prognosis for cathepsin D-positive lung AD patients with an IHC score ≥2+ (P=0.044). Cathepsin D expression was more frequent in TTF-1-negative than in TTF-1-positive ADs (P=0.034), and more frequent in ADs with EGFR wild genotype than mutant EGFR (P<0.001). Regarding AD patients with ALK rearrangements, 4 were positive for Cathepsin D, while 2 were negative. Cathepsin D expression is indicated to be a possible prognostic marker for lung AD and to correlate with a more poorly differentiated form.     

Prognostic value of cathepsin D in breast cancer: comparison of immunohistochemical and immunoradiometric detection methods.

AIM: To test whether immunoradiometric or immunohistochemical detection of lysosomal protease cathepsin D in breast cancer is more predictive of outcome. METHODS: Tumour tissues from 270 primary breast cancer patients were evaluated for the expression of cathepsin D using immunohistochemistry (IH; paraffin embedded tissues) and an immunoradiometric assay (IRMA; cytosol from frozen tissues). Immunohistochemical scores were based on immunoreaction in tumour cells and tumour associated macrophages. RESULTS: IRMA values (cut off 40 fmol/mg cell protein) correlated significantly with IH values. Recorded incidences of positive immunoreaction in tumour cells using two different cut off values were 52% and 35%, respectively. Macrophages stained positive in 31% of tissues. Combined evaluation of tumour cells and macrophages resulted in positivity rates of 59% and 48%, respectively. Node status was the only variable found to correlate with cathepsin D expression. IH results correlated significantly with clinical outcome (median observation time 68 months) in node negative patients (n = 120) but not in node positive patients (n = 145). Cathepsin D positivity as measured by IRMA was not related to clinical outcome in either group. On multivariate analysis in the node negative group, IH detection of cathepsin D appeared to be the only independent factor indicating prognosis. For node positive patients, tumour grade, size, and receptor status were of prognostic relevance. CONCLUSIONS: Because of the simple methodology and the minimal amount of tissue used for analysis, immunohistochemistry was preferred to immunoradiometry for cathepsin D measurement; it also provided more predictive data with respect to prognosis.     

Cathepsin D detected by automated and quantitative immunohistochemistry in breast carcinomas: correlation with overall and disease free survival.

AIM: To determine the prognostic significance and clinical relevance of cathepsin D detected by immunocytochemical assays (ICAs) in breast carcinomas. METHODS: 151 patients presenting with palpable or impalpable breast carcinomas and who had not received any kind of adjuvant chemotherapy or endocrine therapy who were operated from January 1986 to May 1987 were studied. ICAs of tumour specimens were performed in optimal technical conditions (frozen sections, automated immunoperoxidase technique (Ventana), and computer assisted analysis of digitised coloured microscopic images (SAMBA)) to determine cathepsin D immunocytochemical expression. Results of quantitative ICAs were correlated with overall and disease free survival over 8.4 years of follow up in axillary lymph node positive and negative patients. RESULTS: Cathepsin D immunocytochemical expression in tumours of 15% or more was significantly associated with poor overall survival in the whole group and in node positive patients (Kaplan Meier, log rank test p = 0.003 and p = 0.007); however, it was not correlated with survival in node negative patients. Cathepsin D immunocytochemical expression (> 15%) correlated with short disease free (p = 0.015) and short recurrence free survival (p = 0.021) in the group as a whole but not when node positive and negative patients were evaluated separately. CONCLUSIONS: In optimal conditions (automated and quantitative ICAs on frozen sections) cathepsin D immunohistochemical expression is a significant prognostic indicator in terms of overall, disease free, and recurrence free survival; however, there is no correlation when node negative patients are considered separately.     

PTTG‐1 (Securin) immunoexpression in meningiomas correlates with tumor grade and proliferation rate: potential use as a diagnostic marker of malignancy

This study essentially aims to contribute to the immunohistochemical investigation of the use of pituitary tumor transforming gene (PTTG) as a marker of cell proliferation or advanced tumor grade in meningiomas of various WHO grades. In all, 51 cases were recovered in total, 21 Grade‐I, 23 Grade‐II and 7 Grade‐III meningiomas. Mitotic index (MI), Ki‐67/MiB‐1 positivity percentage and PTTG expression were analyzed in correlation to each other as well as to the tumor WHO grades. All three biomarkers showed a high diagnostic significance and a strong association with WHO grades. In comparison, PTTG expression was on a par with the other two indices, and performed very well regarding identification of advanced grade tumors. PTTG may be considered an important diagnostic tool and serve in the future as a novel prognosticator of the biological behavior of all grade meningiomas as well as a useful high‐risk patient selection tool.     

Variable expression of cathepsin B and D correlates with highly invasive and metastatic phenotype of oral cancer

The expression levels of cathepsins B, D, and L in oral cancer surgical specimens were determined using immunocytochemical analysis. Cathepsins B and D are frequently overexpressed in squamous cell carcinomas, whereas their overexpression was less frequent in verrucous carcinoma and basaloid squamous cell carcinomas. Elevated level of cathepsin B in oral carcinomas was significantly associated with advanced tumor stage (P < .05) and poor histologic malignancy grade (P < .001). Increased expression of cathepsin D correlated significantly with the presence of metastasis (P < .05), poor histologic malignancy grade (P < .001), and high proliferation rate (P < .05). Cathepsin L was less frequently overexpressed in oral cancers than cathepsin B and D. These findings indicate that there is a strong cause/effect relationship between the expression levels of cathepsin B and D in oral cancers and their local invasive and metastatic growth patterns. Thus, cathepsins B and D are useful prognostic markers as well as promising gene therapy targets for oral cancer.     

Correlation between histological grade, MIB-1, p53, and recurrence in 69 completely resected primary intracranial meningiomas with a 6 year mean follow-up

Sixty-nine intracranial, totally excised meningiomas were immunostained for MIB-1 and p53 protein expression. According to the 1993 WHO criteria, revised by Perry et al., the 69 meningiomas were classified into: grade I = 54 benign meningiomas, grade II = 10 atypical meningiomas, grade III = 5 malignant meningiomas. The patients were followed until death or for an average of 6.7 years. The 69 meningiomas were divided into two groups, according to the absence (n = 42) or presence (n = 27) of recurrences. In the last group we included 3 patients who died of meningioma recurrence. According to the percentage of MIB-1 positively stained cells, meningiomas were divided into three groups: <1% (n = 36), 1-10% (n = 28), >10% (n = 5). We found the MIB-1 labeling index (LI) <1% in 33 grade I (61%) and in 3 grade II (30%) meningiomas. On the other hand, 7 grade II (70%) and all grade III (100%) meningiomas presented a MIB-1 LI >1%. Correlation between histological grade and MIB-1 LI was statistically significant (p = 0.0006). The correlation between MIB-1 LI and follow-up was also highly significant (p < 0.001): the majority of meningiomas which did not recur (32/42 equal to 76%) were characterized by a low (<1%) MIB-1 LI. In the recurrence group MIB-1 LI was significantly higher than in the disease-free patients' group. Moreover, MIB-1 appeared to be a prognostic parameter not strongly related to the histological grade. In fact, it was significantly higher in recurrent histologically benign meningiomas, as compared with benign meningiomas without recurrence (p = 0.0006). Positive p53 protein expression (>1%) was shown in 26/45 meningiomas (57%), with an LI of 1-10% in 18 (40%) and an LI of >10% in 8 (17%) meningiomas. Although the p53 LI tended to be higher in atypical and malignant meningiomas, no significant correlation was found between the p53 expression and the recurrence (p = 0.05). The authors conclude that quantitative MIB-1 labeling is a useful technique in the routine diagnostic assessment of meningiomas, and helpful in obtaining more information about prognosis and thereby in planning the most suitable treatment.     

Increased Co-Expression of Macrophage Migration Inhibitory Factor and Matrix Metalloproteinase 9 Is Associated with Tumor Recurrence of Meningioma

Background and Objective: We detected the expression of MIF and matrix metalloproteinase 9 (MMP9) in meningiomas to determine whether they are valuable recurrence predictor for meningioma.Methods: 67 cases of meningiomas, including 57 benign tumors (WHO grade I) and 10 non-benign tumors (WHO grade II and III), were collected, and expression of MIF and MMP9 in tissue microarray was evaluated immunohistochemically. The correlations between immunostainings and clinicopathological parameters, as well as the follow-up data of patients, were analyzed statistically.Results: Increased expressions of both MIF (58.2%, 39/67) and MMP9 (55.2%, 37/67) were significantly associated with microvessel density (MVD) of tumor, but only dual high-expression of MIF and MMP9 was in relation to tumor invasion (P=0.016) and tumor recurrence (P=0.001). Based on univariate analysis, histological grade, tumor invasion and co-expression of MIF and MMP9 were significant predictors for recurrence. However, only histological grade and co-expression of MIF and MMP9 in tumor were independent recurrence factors with a hazard ratio of 49.033 (P=0.002) and 37.766 (P=0.002) in multivariate analysis.Conclusions: Together with histological grade, increased co-expression of MIF and MMP9 in tumor might be a valuable predictor for recurrence, especially for benign meningiomas.     

组织蛋白酶D在小鼠肺腺癌发生发展中的表达特点及其意义

目的探索组织蛋白酶D(CTSD)在肺腺癌发生发展中的表达特点及其意义。方法使用氨基甲酸乙酯腹腔注射建立BALB/c小鼠肺腺癌模型;蛋白质组放射性核素相对标记和绝对定量(i TRAQ)分析筛选差异表达蛋白;免疫组织化学和Western blotting检测蛋白在肺腺癌不同病理时期的表达变化特点。结果 CTSD蛋白在肺腺癌早期表达较对照组明显增强;免疫组织化学和Western blotting检验分析发现,随着肺腺癌病程进展,CTD表达呈上升趋势,在肺腺癌晚期,实验组为对照组13.7倍;出现肝转移实验组小鼠肺组织CTSD呈现不同异构体。结论CTSD是肺组织癌变过程中的重要蛋白,其异常表达和修饰可能在肺腺癌发生、发展和转移中起重要作用,可能成为肺腺癌早期诊断的分子指标。     

Correlation between cathepsin D expression and p53 protein nuclear accumulation in oesophageal squamous cell carcinoma

AIM: The lysosomal protease cathepsin D has been reported to be associated with tumour progression in malignant tumours. Expression of the gene encoding cathepsin D is known to be stimulated by oestrogen in mammary cancer cells. Recent experiments revealed that a p53 DNA binding site is located in the promoter region of the cathepsin D gene. This fact indicates that cathepsin D expression may correlate with p53 protein expression. The purpose of this study is to evaluate the expression patterns of the cathepsin D and p53 proteins in oesophageal squamous cell carcinoma (SCC). METHODS: In 154 patients with oesophageal SCC, expression of the cathepsin D and p53 proteins was measured in tumours by means of immunohistochemistry using monoclonal antibodies against cathepsin D (clone, 1C11) and p53 (clone, BP53-12). RESULTS: Cathepsin D was detected in tumour cells, although it was not found in normal oesophageal epithelium adjacent to carcinoma. High cathepsin D expression (positive tumour cells > 10%) was detected in 76 of 154 cases (49%) and high p53 nuclear expression (positive tumour cells > 50%) was detected in 70 cases (46%). High cathepsin D expression was significantly associated with invasive tumour growth (p = 0.002), poor prognosis (p = 0.049), and nuclear accumulation of p53 protein (p = 0.001). Overexpression of both p53 and cathepsin D was seen in 45 of the 154 cases (29.2%). In addition, there was a positive correlation between the cathepsin D index (percentage of cathepsin D positive tumour cells) and Ki-67 labelling index (percentage of Ki-67 positive tumour cells) in 154 oesophageal SCCs (rho = 0.257; p = 0.009). However, in multivariate survival analysis, cathepsin D expression by the tumours was not an independent prognostic factor in patients with oesophageal SCC (p = 0.236). CONCLUSIONS: The expression of cathepsin D by cancer cells may play an important role in the invasive growth of oesophageal SCC. Overexpression of both p53 and cathepsin D was seen frequently in tumours; p53 gene abnormalities may correlate with cathepsin D overexpression in oesophageal SCC.     

Methylation status of TP73 in meningiomas

Deletions at 1p are frequent in meningioma and represent a genetic marker associated with the genesis of atypical WHO grade II forms. Previous mutational analysis of TP73, a structurally and functionally TP53 homologous gene located at 1p36.33, failed to demonstrate a significant rate of sequence variations linked to gene inactivation in meningiomas with 1p loss. As an alternative, TP73 may be inactivated through aberrant 5' CpG island methylation, a primary mechanism participating in the inactivation of tumor suppressor genes during tumorigenesis. We determined the methylation status of the TP73 gene in a series of 60 meningiomas (33 grade I, 24 grade II, and 3 grade III samples), including tumors with deletion at 1p (n=30) and with intact 1p (n=30). Aberrant methylation was detected in 10 cases (33%) with 1p deletion and in 3 tumors (10%) with retention of alleles at this chromosome arm. The distribution of the 13 cases of methylation according to malignancy grade was 7 grade I, 5 grade II, and 1 grade III tumor. Accordingly, although TP73 aberrant methylation was more frequent in meningiomas with 1p deletion (P<0.05), no association with the grade of malignancy could be established. These findings, together with the previously reported increased TP73 expression in malignant meningiomas suggest that opposing functions of this gene may characterize distinct subsets of tumors: suppressed or reduced expression as a result of CpG methylation in some grade I-grade II tumors, and enhanced expression in some more malignant forms.     

Cathepsin D in invasive ductal NOS breast carcinoma as defined by immunohistochemistry. No correlation with survival at 5 years.

Cathepsin D expression was assessed by immunohistochemistry in 59 node-negative and 77 node-positive infiltrative ductal not otherwise specified (NOS) breast carcinomas and compared with overall survival at 90 months. Cancer cells in 60% (81/136) of the tumors expressed cathepsin D. In the stroma of 33% (18 of 55) cathepsin D negative tumors, numerous strongly cathepsin D positive, benign macrophage-like cells were found. Multivariate analysis showed no significant correlation of cathepsin D expression and overall survival for all patients for node-negative and node-positive patients and for patients with vimentin-positive and -negative tumors. However, in node-negative but not in node-positive patients, a trend for better survival for patients with cathepsin-positive vimentin-negative tumors and worse survival for those with cathepsin-positive vimentin-positive tumors was noted. Due to the low number of patients in these subgroups, neither trend reached significance. Cathepsin D expression was independent of patient age, size, and histologic grade of tumor, and vimentin expression. However, in the node-positive group, negative correlation of cathepsin D and vimentin expression was found. We suggest that prognostic significance of cathepsin D in infiltrative ductal NOS breast carcinomas may be associated with the pathway of its synthesis rather than with its mere presence in tumor cells.     

Allelic gain and amplification on the long arm of chromosome 17 in anaplastic meningiomas

Using comparative genomic hybridization (CGH) we have previously identified amplification at 17q21-qter as a common aberration in anaplastic meningiomas but not in atypical or benign meningiomas (19). To define the amplified genomic region, we analyzed 44 meningeal tumors, including 7 benign meningiomas of World Health Organization (WHO) grade 1,19 atypical meningiomas (WHO grade II) and 18 anaplastic meningiomas (WHO grade III) at 46 chromosome 17 loci (including 42 17q loci). In line with the CGH data we found evidence of increased numbers of alleles on 17q. The incidence rose with malignancy grade, culminating at 61% (11 of 18 cases) in the anaplastic meningioma group. The majority of cases showing increased allele numbers had, on average, low-level allelic gains (relative increase in allele dosage of 2- to 5-fold). Amplification of alleles (defined here as an average relative increase in allele dosage of more than 5 times) was detected in 2 anaplastic meningiomas. The amplification patterns in these tumors defined a number of common regions of amplification/increased allele copy number, the best defined include one between D17S790 and D17S1607 and one between D17S1160 and PS6K. Real-time PCR analysis of the PS6K candidate gene revealed no high-level amplification despite this affecting adjacent loci. Our findings are fundamental for the identification of the gene(s) in 17q22-q23 that is (are) the target(s) for increased copy number in anaplastic meningiomas and possibly other tumor types.     

Role of p53 gene mutation in tumor aggressiveness of intracranial meningiomas.

The mutations that occur in the p53 tumor suppressor gene have been studied in various human malignant tumors. However, little is known about this gene in meningiomas. To investigate the relationship and frequency of p53 gene mutations, the p53 polymerase chain reaction-single stranded conformational polymorphism (PCR-SSCP) and immunohistochemical study were performed on the 41 intracranial meningiomas (21 benign, 11 atypical, and 9 malignant). The higher the p53 protein expression rate, the poorer the histologic grade (9.5%, 72.7%, and 88.9% in benign, atypical and malignant meningioma, respectively) (p=0.000). The p53 protein expression rate was higher in recurrent meningioma (71.4%) than in nonrecurrent meningioma (10.5%) (p=0.002). PCR-SSCP method was performed in positive p53 protein immunoreactivity cases. p53 gene mutation rate was higher in the atypical (62.5%) and malignant (25%) meningiomas than in the benign meningioma (0%) (p=0.232). Also, the rate was higher in recurrent menigioma (20%) than in nonrecurrent meningioma (0%) (o=0.495). Among five to eight exons of the p53 gene, the mutation was observed on exon 7 more frequently. In conclusion, p53 immunoreactivity and p53 gene mutation are closely correlated with histologic grade and histologic atypia of intracranial meningiomas. p53 gene mutation would be considered as a useful marker to detect the progression of intracranial meningiomas.     

Estrogen and progesterone receptors in meningiomas: immunohistochemical (Mib-1, p53) and clinico-morphological correlations

We studied 98 meningiomas including 89 benign, 5 atypical, and 4 anaplastic tumors to determine the immunohistochemical expression of estrogen and progesterone receptors and its prognostic value in comparison to histological grade, Mib-1 and p53. Estrogen and progesterone receptor positivity was observed in 63% and 5% of the cases, respectively. In 79% of meningiomas only a minimal proliferative activity was documented, whereas in 36% we detected an overexpression of the p53 oncoprotein. Anaplastic meningiomas were constantly negative for PgR, ER, and highly positive for Mib-1; 75% were positive for p53. A statistical correlation was demonstrated between p53 protein and Mib-1. Specifically the p53-negative meningiomas were frequently negative for Mib-1 (p = 0.002); conversely the lesions strongly positive for Mib-1 were p53-positive (p = 0.001).     

Immunohistochemical study of Ki-67 (MIB-1), p53 protein, p21WAF1, and p27KIP1 expression in benign, atypical, and anaplastic meningiomas

Histologic grading of meningiomas has prognostic and clinical therapeutic implications. Meningiomas were histologically classified into 3 different World Health Organization grades. Grade II, an atypical meningioma, was defined by major and various minor histologic criteria. However, these histologic criteria sometimes are not fulfilled, and other criteria are necessary. We studied and analyzed the immunohistochemical expression of MIB-1, p53, p21WAF1, p27KIP1 proteins in 146 cases of meningiomas, including 109 benign, 27 atypical, and 10 anaplastic meningiomas. Most of the benign meningiomas expressed low MIB-1 labeling index (mean, 1.5%), and fewer cases had p53 protein expression. In contrast, the anaplastic meningiomas had a high labeling index of MIB-1 (mean, 19.5%) and always expressed p53 protein, with a mean labeling index of 6.3%. The atypical meningiomas had MIB-1 and p53 labeling indexes in the range between benign and anaplastic meningiomas, with mean labeling indexes of 8.1% and 3.5%, respectively. These expressions were statistically significant among benign, atypical, and anaplastic meningiomas (P <.001). We conclude that the immunohistochemistry of MIB-1 and p53 protein will be valuable in discriminating atypical meningiomas from benign or anaplastic meningiomas, at least in histologically borderline cases. In addition, we also found direct correlation of p21 and inverse correlation of p27 expressions in meningiomas with increasing histologic grade and proliferative index.