Search for estrogen receptors in human meningioma tissue sections with a monoclonal antibody against the human estrogen receptor.

Meningiomas are rich in progestin receptors, whereas estrogen receptors (ER) are virtually undetectable. The present experiments were performed to evaluate whether the absence of ER from the majority of human meningioma cytosols can be attributed to: occurrence of only a small number of ER-positive cells in an otherwise ER-negative tissue; resistance of nuclear receptors to extraction; or impairment of steroid binding. Twenty-one specimens were selected from our total series of 67 meningiomas. Based on cytosol assays, five of these meningiomas were considered to be ER positive (10-42 fmol/mg protein) and five had marginal ER concentrations (4-9 fmol/mg protein), whereas the remaining tissues were ER negative. For comparison, human breast cancer tissues were used. Tissues were sectioned at 6 micron and stained immunocytochemically using a monoclonal antibody against the human ER. The breast cancer specimens showed specific nuclear staining in part of the tumor cells. The sensitivity of the immunocytochemical assay was found to be sufficient to detect staining in breast cancer tissues containing as little as 17 fmol ER/mg cytosol protein. No specific staining was observed in meningioma tissues. It is concluded that the majority of meningiomas are truly devoid of ER and that the estrogen binding agent detected in low concentration in some meningioma cytosols is immunologically different from the human breast cancer ER. The presence of progestin receptors in meningioma apparently does not require the continuous presence of ER.

Intermediate filaments in meningiomas.

The presence of intermediate filaments (IF) (diameter 10 nm) is a characteristic electron microscopic finding in the cytoplasm of meningioma cells. To identify these IF, immunohistochemical staining for cytokeratins and vimentin and two-dimensional (2-D) gel electrophoresis followed by immunoblot analysis were applied to a group of 16 meningiomas. Thirteen meningiomas were obtained directly from surgery and three came from an autopsy in which they were found in close proximity as discrete tumor masses. Except for the angioblastic type, all major histological variants were represented (nine transitional, four syncytial, and three fibroblastic). None of the meningiomas stained for epithelial or internal organ cytokeratins. With monoclonal antibodies, each of the meningiomas stained positively for vimentin. Two-D gels revealed vimentin and vimentin breakdown products as the only IF present; these findings were verified by immunoblots. The study concludes that vimentin is the IF present in fibroblastic, syncytial, and transitional meningiomas.

An ultrastructural and immunocytochemical analysis of leptomeningeal and meningioma cultures.

Using immunocytochemical methods, we localized several glycoproteins of the extracellular matrix to leptomeningeal cells and meningiomas in vitro. Three cell lines derived from normal human leptomeninges and seven from meningiomas were studied by indirect immunofluorescence to evaluate the cellular production of fibronectin, laminin, collagen type IV, and procollagen type III. All leptomeningeal cell lines stained intensely and uniformly for all matrix proteins; all meningioma cell cultures stained uniformly, but the intensity of staining varied considerably. After removal of the cells in culture adherent to glass with 25 mM ammonium hydroxide, indirect immunofluorescence demonstrated an exuberant residual extracellular residue enriched with fibronectin, laminin, collagen type IV, and procollagen type III. Electron microscopic examination of all leptomeningeal and meningioma cultures revealed desmosomes and dense tonofilament formation; in addition, granular, filamentous basement membrane-like material was abundant in the extracellular spaces of all cultures. Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of the cell layer of two leptomeningeal and four meningioma cultures showed production of interstitial collagen types I and III; diethylaminoethyl (DEAE)-cellulose chromatography of the medium demonstrated preferential production of procollagen type I. Our findings show conclusively that normal arachnoid cells in vitro synthesize several of the collagen subtypes and may be responsible for the "fibrous response" of the leptomeninges to trauma, infection, or infiltration by tumor. The similarities between leptomeningeal cells and meningiomas demonstrated by electron microscopy and by indirect immunofluorescence support the notion that meningiomas are derived from arachnoid cells. The localization of various mesenchymal glycoproteins within the intra- and extracellular spaces and the ubiquity of specialized intercellular junctions suggest that leptomeningeal cells in culture have the potential to behave like both stromal and epithelial cells.

Intracellular mucoid changes in tumor cells of meningiomas: a manifestation of polyvinylpyrrolidone (PVP) effect on tissues with mesenchymal characteristics.

In two cases of meningiomas in Taiwanese patients, extensive intracellular mucoid changes were found within tumor cells, together with deposits of polyvinylpyrrolidone (PVP) granules. Both patients had in the past received intravenous PVP as a plasma expander. Recipients of PVP have previously been reported to develop a form of PVP thesaurismosis with concomitant mucoid changes in the cells storing this substance. Such changes, as a rule, were limited to cells of mesenchymal origin. By storing PVP granules and undergoing mucoid changes as a result, meningioma tumor cells behave as cells with mesenchymal characteristics.

Brain glycoprotein in tumours of the nervous system.

We studied various tumours of the nervous system by the immunofluorescence technique using an anti-brain specific alpha 2 glycoprotein antiserum (anti-NSA3 antiserum). We found the antigen in 24/27 astrocytomas and 4/4 oligodendrogliomas but in none of the 8 meningiomas tested. There was an identity between the astrocytoma/oligodendroglioma antigen and that of normal brain as shown by the immunoprecipitation technique. By the immunofluorescence technique using inhibition of the antiserum we demonstrated that the tumour antigen is devoid of some specific nervous system determinants present in normal brain.

Simian virus 40-related DNA sequences in a human brain tumor.

Papovaviruses can induce experimental brain neoplasms in animals, and some papovaviruses have been implicated in the formation of various human tumors. We examined a series of seven human brain tumors removed at craniotomy for the presence of viral DNA sequences by the technique of DNA-DNA hybridization. Simian virus 40 (SV40) DNA was labeled in vitro and used as a "probe" for detecting related DNA sequences in cellular DNA extracted from brain tumors. SV40-related DNA sequences were found in DNA extracted from one tumor, a glioblastoma multiforme. It was calculated that approximately 1.2 viral genome equivalents per diploid cell were present in the tumor. Since the rate of reassociation of the probe deviated from ideal second-order kinetics, it is surmised that either only a portion of the SV40 genome was present in tumor cells or, alternatively, that the probe detected a related human papovavirus.

Secretory meningioma. A distinct subtype of meningioma.

Six meningiomas with abundant hyaline inclusions (pseudopsammoma bodies) were studied. As seen by light and electron microscopy, hyaline inclusions are composed of material of varying structures located in intracellular lumina lined by microvilli. A remarkable pericytic proliferation within the vessel walls was found in five cases. In all six cases, immunohistochemical examination for multiple antigens showed positive staining for carcinoembryonic antigen and epithelial membrane antigen in inclusions and surrounding cells. Weak positivity was found for keratin and secretory component in five cases and for alpha-1-antitrypsin and IgM in four cases. It is concluded that secretory meningioma is a distinct type of meningioma, usually meningothelial in type. It shows characteristic light-microscopic, ultrastructural, and immunohistochemical features of epithelial and secretory differentiation with accumulation of secretory material in the form of hyaline inclusions; marked vascular pericytic proliferation is also frequently present.

Meningioma, meningeal hemangiopericytoma (angioblastic meningioma), peripheral hemangiopericytoma, and acoustic schwannoma. A comparative immunohistochemical study.

The relationship between meningeal hemangiopericytoma (angioblastic meningioma), meningiomas of meningothelial derivation, and peripheral hemangiopericytoma is controversial; and immunohistochemical studies have yielded conflicting results. Likewise, immunohistochemistry has been touted as a reliable means of differentiating fibrous meningioma from acoustic schwannoma. By the immunoperoxidase method, we studied 40 meningiomas (11 meningotheliomatous, four transitional, 11 fibrous, three secretory, four metaplastic, one xanthomatous, one papillary, four atypical, one malignant), five arachnoid granulations, 13 angioblastic meningiomas, nine peripheral hemangiopericytomas, and seven acoustic schwannomas. Antisera to vimentin, epithelial membrane antigen (EMA), keratin, S-100 protein, carcinoembryonic antigen (CEA), desmin, factor VIII, Ulex europeaus, and glial fibrillary acidic protein (GFAP) were utilized. All meningiomas and arachnoid granulations stained for vimentin and EMA; 15% and 12% of meningiomas were S-100 and keratin positive, respectively. The latter was noted primarily in areas of secretory (pseudopsammomatous) differentiation. In contrast, all angioblastic meningiomas stained for only vimentin. This profile of immunoreactivity was also seen in the peripheral hemangiopericytomas, with the exception of single cases that stained focally for EMA and S-100 protein, respectively. Acoustic schwannomas all stained positively for S-100 protein, vimentin, and were variably reactive for EMA, a pattern not distinct from meningioma. We conclude that (a) meningiomas express both epithelial and mesenchymal markers as do arachnoid granulations, (b) that angioblastic meningiomas demonstrate only mesenchymal markers, (c) that angioblastic meningiomas express identical markers to peripheral hemangiopericytoma and should thus be considered a variant thereof, (d) among meningiomas, CEA and keratin appear to be relatively specific markers for the "secretory" variant, and (e) because of overlap in S-100 and EMA reactivity, these markers are unreliable in differentiating meningioma from acoustic schwannoma.

Soft-tissue and meningeal hemangiopericytomas: an immunohistochemical and ultrastructural study.

The debate on the nosologic position of hemangiopericytomas of the meninges has been based mainly on light microscopic and ultrastructural considerations; recent immunohistochemical studies have yielded controversial results. We have used a panel of antibodies to vimentin, desmin, actin, S100 protein, epithelial membrane antigen, cytokeratins, Leu-7, factor VIII-related antigen and type IV collagen to compare the immunophenotype of 10 soft-tissue and seven meningeal hemangiopericytomas. The immunophenotypic profile of these tumors is identical, and differs from that of meningiomas in that epithelial membrane antigen and cytokeratin are not present. The vascular pattern occurring in some meningiomas can simulate true hemangiopericytomas of the meninges. Immunohistochemical studies should allow their distinction in each instance. Meningeal and soft-tissue hemangiopericytomas display similar ultrastructural features.

Epithelial differentiation in meningiomas. An immunohistochemical, histochemical, and ultrastructural study--with review of the literature.

Meningiomas possess features indicative of epithelial differentiation. The present study further documents this finding by a multimodality approach on serial sections from 25 meningiomas of all histologic and clinical categories. Standard light microscopic examination, immunohistochemical staining with a variety of epithelial and nonepithelial markers, and histochemical staining for mucin were performed on each case. Directed electron microscopic examination was performed on selected examples of epithelial feature-positive and -negative cases. All cases were immunoreactive for vimentin and epithelial membrane antigen. Thirty-two percent were reactive for cytokeratin and 39% for S-100. Twenty percent showed mucin positivity by histochemistry. Electron microscopic examination of cytokeratin-positive cases showed either intracellular lumina (secretory areas) or cytoplasmic tonofibrils, whereas cytokeratin-negative tumors lacked lumina and tonofibrils. Previous studies showing epithelial features in meningiomas are reviewed with emphasis on the studies using immunohistochemistry. These histochemical, immunohistochemical, and ultrastructural characteristics are of utility in the examination of tumors of suspected meningeal origin, particularly when dealing with atypical presentations or histomorphologic features.

Epithelial membrane antigen and cytokeratin expression by meningiomas: an immunohistological study.

Thirteen meningiomas of varying light microscopic features were studied immunohistologically using a panel of monoclonal antibodies directed against epithelial, mesenchymal, and neural components. All 13 meningiomas showed expression of epithelial membrane antigen, vimentin, and S100 protein, as did normal meninges. Five of the 13 meningiomas also showed focal expression of cytokeratins, with double labelling showing expression of cytokeratins and vimentin by different cells. The cytokeratin expression was especially noticeable in cells surrounding the hyaline bodies of meningiomas. These results provide further evidence that meningiomas have features of both mesenchymal and epithelial tissues.

Cryostat section assay of oestrogen and progesterone receptors in meningiomas: a clinicopathological study.

Oestrogen receptors and progesterone receptors were measured in the cytosols from cryostat sections of 45 meningiomas from 40 patients (12 men, 28 women) using an isoelectric focusing technique. Near fascimile adjacent sections from the same tissue blocks were stained and examined to determine the histological subtype of the neoplasms. Appreciable levels of progesterone receptor (greater than 10 fmol/mg cytosol protein) were present in 24 (53.3%) of of the neoplasms, but no clinically important oestrogen receptor was detected in any of the tumours. Competitive binding studies on control tissue confirmed the specificity of the assay procedures. No correlation was found between progesterone receptor state and the age, sex, or menopausal state of the patients, or the histological subtype and site of the neoplasms. Four of the patients studied had multiple intracranial neoplasms, which in two were of differing progesterone receptor state. The presence of specific progesterone receptor in meningioma cytosols raises the possibility of hormonal manipulation in the treatment of this group of neoplasms.

Expression of muscarinic binding sites in primary human brain tumors.

The expression of muscarinic binding sites was examined in a collection of primary brain tumors of different cellular origins and various degrees of dedifferentiation, as compared to control specimens. Eleven gliogenous tumors were examined, all of which contained substantial amounts of muscarinic binding sites. Most of the other tumor types examined did not display detectable binding of [3H]N-methyl-4-piperidyl benzilate ([3H]4NMPB). Scatchard analysis indicated the existence of homogeneous antagonist sites in both normal forebrain and glioblastoma multiforme, with Kd values of 1.2 nM and 0.9 nM, respectively. The density of muscarinic binding sites varied between tumors from different patients, and also between specimens prelevated from different areas of the same tumor. This variability, as well as the average density of binding sites, appeared to be larger in highly malignant tumors than in less malignant ones. In contrast, the density of muscarinic receptors from control specimens was invariably high, but within the same order of magnitude. To test whether the muscarinic binding activity in the brain tumors is correlated to other cholinoceptive properties, cholinesterase activity was also examined. Individual data for density of [3H]4NMPB binding sites were then plotted against corresponding values of cholinesterase activity. The pattern of distribution of these values was clearly different in tumor specimens, when compared to that observed in samples derived from non-malignant brain. Our observations indicate that human brain cells of gliogenous origin are capable of expressing muscarinic binding sites, and that, if a correlation exists between muscarinic receptors and cholinesterase levels in gliogenous tumors, it differs from that of non-malignant brain tissue.

Gonadal steroid receptors in meningiomas.

Oestrogen receptor (ER) analysis was performed in 70 meningiomas with an enzyme immunoassay, using monoclonal antibodies against human oestrogen receptor protein (oestrophilin) and with a sensitive radioligand binding assay, using 125I-oestradiol as radioligand. Low levels of ER immunoreactivity were found in tumours from 51% of patients, whereas ER binding activity was demonstrated in 40% of the meningiomas examined. In 8 (11%) tissue samples multiple binding sites for oestradiol were observed. The immunoreactive binding sites corresponded to the classical, high-affinity ER. In ligand binding studies, however, measurement of classical ER was considerably influenced by a second low-affinity, high-capacity oestrogen binding component even at low ligand concentrations. 3H-methylpromegestone and 3H-methyltrienolone, a synthetic gestagen and androgen, were used for concurrent determination of the progesterone receptor (PR) and androgen receptor (AR) binding activity. High concentrations of PR were detected in 53 (76%), whereas moderate levels of AR binding sites were demonstrated in 33 (47%) tumours. A positive correlation between ER immunoreactivity and AR binding activity is indicative for an oestrogen regulation of AR via the ER system. The presence of gonadal steroid receptors in a large proportion of meningiomas and the tendency for a dependence of receptor concentrations on the histological subtype could have implications for tumour therapy.

Cellular blue nevus ("melanocytoma") of the spinal meninges: electron microscopic and immunohistochemical features.

A primary cellular blue nevus (melanocytoma) of the spinal canal in a 21-year-old woman is reported. Light microscopic examination revealed a melanotic neoplasm with histological patterns resembling schwannoma, dermal nevi, and neuroblastic-like tumor. The ultrastructural features of the neoplastic cells were similar to those in dermal blue nevi and melanomas. There was no evidence of arachnoidal cell differentiation. Immunohistochemistry revealed positive reactions for S-100 protein and neuron-specific enolase in many cells and no reactions for glial fibrillary acidic protein, cytokeratins, epithelial membrane antigen, 70-kD neurofilament protein, or Leu-7. Vimentin was strongly positive in the melanocytic cells as well as in the arachnoidal cells of involved meninges. The ultrastructural and immunohistochemical features support the nevoid nature of this tumor, which is frequently mislabeled as "melanotic meningioma."

Intracytoplasmic lumina in meningioma: an ultrastructural and immunohistological study.

Three surgically removed meningotheliomatous meningiomas with hyaline inclusions or pseudopsammoma bodies were studied. Ultrastructurally, the lumina seemed to be predominantly intracytoplasmic, defined by a systemic unit membrane; they displayed abundant microvilli and contained granular or filamentous material, vacuoles, vesicular bodies, and lamellar structure. The cytoplasm surrounding the intracytoplasmic lumina was electron-dense and contained tonofilaments and desmosomal junctions. All three meningiomas showed expression of carcinoembryonic antigen, cytokeratin, and epithelial membrane antigen in the cells surrounding the hyaline bodies. Keratin, alpha-1-antitrypsin, and immunoglobulin M showed weak positive staining. There was widespread vimentin except in the cells with hyaline inclusions. Glial fibrillary acidic protein and S100 were negative. These results provide additional confirmation of immunohistochemical data that can serve as evidence for epithelial and secretory differentiation in meningiomas.

Multiparameter flow cytometric analysis of neoplasms of the central nervous system: correlation of nuclear antigen p105 and DNA content with clinical behavior.

Analysis of the DNA content of various solid tumors and hematological malignancies may provide useful prognostic information. To date, however, there has been a striking lack of correlation between DNA content in neoplasms of the central nervous system and clinical behavior. Simultaneous quantitation of DNA content and proliferation-associated nuclear antigen (p105) by flow cytometry was performed on paraffin-embedded tissues representing three major groups of central nervous system neoplasms--1) 21 astrocytic tumors, 2) 13 pituitary tumors, and 3) 19 meningiomas--and the results were correlated with clinical behavior. All 4 well-differentiated gliomas were diploid, while 3 of 9 anaplastic astrocytomas and 1 of 8 glioblastomas had a demonstrable aneuploid peak. Three of 13 pituitary tumors had an identifiable aneuploid peak, while only 2 of 19 meningiomas had an aneuploid DNA content. Cell-cycle analysis of the malignant gliomas revealed a significantly higher proliferative index (PI, %S + G2M) compared with the well-differentiated astrocytomas (P less than 0.05). Within the subgroup of diploid anaplastic astrocytomas, however, extended patient survival appeared to be associated with a higher PI. For diploid pituitary adenomas, the PI was consistently lower in the 3 tumors that recurred than it was in the remaining 8 adenomas. Nuclear antigen quantitation of diploid tumors showed a wide range of p105 expression in G0G1 cells, suggesting that, within each tumor, the cells are heterogeneous with respect to proliferative activity. Aneuploid nuclei of glial tumors showed enhanced expression of p105 relative to diploid cells of the same specimen. In pituitary tumors, the median G2M/G0G1 fluorescence ratio for p105 was significantly higher (P less than 0.05) for the 3 diploid recurrent tumors than for those that did not recur. These data support the assumption that the aggressive clinical course of malignant glial neoplasms may be related to an abnormal DNA stemline and/or an alteration in cell proliferative activity. Cell cycle analysis and measurement of p105 by this technique may provide information useful from both a prognostic standpoint and in directing adjuvant therapy.

Sex hormone receptors in intracranial tumours and normal brain.

Fifty-four intracranial neoplasms (29 meningiomas, 16 gliomas, seven acoustic neuromas and two cerebral metastases) and nine specimens of normal brain were evaluated for specific progesterone and oestrogen receptor proteins using a dextran-coated charcoal assay and Scatchard plot analysis. Sixteen meningiomas (55%) were progesterone receptor (PgR) positive (median 52; mean 120; range 10-486 fmol mg-1 cytosol protein), whilst all were oestrogen receptor negative (ER-). Two (28%) of the acoustic neuromas contained small amounts of PgR protein, but all seven were ER-. None of the gliomas, cerebral metastases or specimens of normal brain contained ER or PgR protein. Analysis of PgR status and clinicopathological data suggest that there is no predictive correlation between PgR status and the patients age, sex, reproductive status, tumour histology or tumour behaviour. These results again suggest that in meningiomas PgR proteins are not modulated by oestrogens acting through ER. This finding may explain the failure of antioestrogen therapy to influence the growth of meningiomas. The significance of PgR protein in intracranial meningiomas is discussed with respect to tumour heterogeneity and implications for research with gene probes.

Primary leptomeningeal ependymoblastoma. Case report.

Ependymoblastoma is considered to be a primitive malignant glioma with ependymal differentiation. This rare tumor occurs in very early life and shows rapid growth and a diffuse infiltration through the leptomeningeal space. The tumor cells are highly immature, with numerous mitoses and multilayered ependymal rosettes. The ependymoblastoma described in this report was found in a 17-year-old girl. In spite of detailed clinical and postmortem examinations, no definite primary site was identified in the neuraxis. The lesion spread predominantly throughout the leptomeningeal space. Histological analysis strongly suggested that this tumor originated from a heterotopic glial nest in the subarachnoid space. The absence of immunohistochemical neural tissue markers, glial fibrillary acidic protein, S-100 protein, neuron-specific enolase, and neurofilaments ruled out neuronal or glial differentiation. The authors were unable to find any previous report of primary leptomeningeal ependymoblastoma.

Correlation of meningioma hormone receptor status with hormone sensitivity in a tumor stem-cell assay.

Several investigators have detected progesterone receptors in a high percentage of meningioma specimens and have noted progesterone receptors to be more common than estrogen receptors in these specimens. However, a functional significance of such hormone receptor positivity in control of meningioma growth has not been described. This paper describes a paired test of the estrogen and progesterone receptor assay as the biochemical assay and of the human tumor stem-cell clonogenic assay (HTSCCA) as the functional assay in 17 meningioma specimens. Only one (6%) of the 17 specimens was estrogen receptor-positive, while 11 (69%) of 16 specimens were progesterone receptor-positive. The HTSCCA revealed that only two (15%) of 13 specimens were sensitive to estradiol while five (31%) of 16 specimens were sensitive to progesterone. Comparison of progesterone results for the 15 specimens on which both hormone receptor assay and HTSCCA were performed revealed correlation in a majority of cases; four specimens were positive for both assays and five specimens were negative for both assays. No specimen that was negative for progesterone receptors was sensitive to progesterone by HTSCCA. These results suggest that the hormone receptor and sensitivity pattern of meningiomas may differ from that of breast cancer, and that progesterone addition or ablation may be a reasonable therapeutic approach for meningiomas.