Immunohistochemical recognition of human neuroepithelial tumors by anti-Leu 7 (HNK-1) monoclonal antibody

Lucien J. Rubinstein: enduring contributions to neuro-oncology

Dr. Lucien Rubinstein is best remembered for his significant contributions to the field of neuropathology, particularly in the classification of nervous system tumors. His accomplishments in basic neuro-oncology and in the formulation of diagnostic principles reflected a unique talent for synthesizing fundamental clinicopathological concepts based on skillful diagnostic investigation and a thorough understanding of neurobiology. Dr. Rubinstein was the leader in the establishment of cell cultures from central nervous system (CNS) tumors. He meticulously analyzed both light and electron microscopic features of CNS tumors, recorded his findings, and patiently drew sketches to be shared generously with his colleagues and students. As a pioneer in neuropathology, in his work Dr. Rubinstein set the foundation for many enduring concepts in neurosurgery, neuro-oncology, neurology, and basic tumor biology.

Galectin-3 as an immunohistochemical tool to distinguish pilocytic astrocytomas from diffuse astrocytomas, and glioblastomas from anaplastic oligodendrogliomas

The distinction of astrocytomas and oligodendrogliomas, mainly pilocytic astrocytomas (PILOs) from infiltrating astrocytomas and oligodendrogliomas (ODs), and high-grade oligodendrogliomas from glioblastomas (GBMs), poses a serious clinical problem. There is no useful immunohistochemical (IHC) marker to differentiate these gliomas, and sometimes the differential diagnosis between them is arbitrary. We identified galectin-3 (Gal-3) as a possible tool to differentiate them based on gene expression profiles of GBMs. We confirmed the differential expression in 45 surgical samples (thirteen GBMs; seven PILOs; 5 grade II ODs; 5 anaplastic oligodendrogliomas [AODs], including 2 Oligo-astrocytomas; 8 diffuse astrocytomas [ASTs], and 7 non-neoplastic samples) by quantification of Gal-3 gene expression by real-time quantitative PCR (rt-PCR). Higher expression of Gal-3 was observed in GBMs and PILOs than in OD, AODs and ASTs. The IHC expression of Gal-3 was evaluated in 90 specimens (fifteen PlLOs, fourteen ASTs, 10 anaplastic astrocytomas, fifteen GBMs, eleven ODs, fifteen AODs, and 10 dysembryoplastic neuroepithelial tumors). The mean labeling score for Gal-3 determined according to the percentage of labeled cells in the tumor bulk was significantly different in GBMs versus AODs and in PILOs versus ASTs. Hence, Gal-3 is differentially expressed in central nervous system tumors, making IHC detection of Gal-3 a useful tool in distinguishing between these gliomas.

The HNK-1 carbohydrate epitope in the eye: basic science and functional implications

The HNK-1 carbohydrate epitope is part of many cell membrane and extracellular matrix molecules. It has been implicated in cell to cell and cell to extracellular matrix adhesion, and antibodies to the HNK-1 epitope are emerging as a versatile tool in eye research. They have been used to identify a novel cell type in the human eye, the subepithelial matrix cells that reside in the inner connective tissue layer (ICTL) of the ciliary body. Although these cells resemble fibroblasts in ultrastructure, they form a distinct cell population that differs in its antigenic profile from fibroblasts of other tissues. These cells are associated with the elastic fiber system of the ICTL. Other structures in the human eye that harbor the HNK-1 epitope in a nonrandom pattern are the ciliary and iris epithelia, the zonular lamella, the lens capsule, the retina, glial cells of the optic and ciliary nerves, and scleral fibroblasts. The HNK-1 epitope in the eye appears early during embryonic development and is phylogenetically conserved, but many interspecies differences exist in its distribution. The role of the HNK-1 epitope may be to structurally stabilize the ciliary body and the retina, and to participate in zonular attachments. The HNK-1 epitope has been linked with many common eye diseases. The subepithelial matrix cells seem to be susceptible to undergo irreversible damage as a result of glaucoma, thermal injury, and tissue compression. This epitope has proved to be useful in identifying intraocular deposits of exfoliation syndrome. It can explain the adhesiveness of exfoliation material. Intraocular exfoliation material differs in HNK-1 immunoreactivity from the extraocular fibrillopathy of exfoliation syndrome and its presence in fellow eyes also argues against the concept of unilateral exfoliation syndrome. The HNK-1 epitope is found in the extracellular matrix of secondary cataract and anterior subcapsular cataract, and it may contribute to their pathogenesis. Finally, the HNK-1 epitope can be used to trace neuroepithelial derivatives of the optic vesicle in developmental anomalies and in tumors of the eye. Eventual identification of molecules that bear the HNK-1 epitope in the eye will likely shed light on many aspects of ocular physiology and pathobiology

Tumors of the choroid plexus

Choroid plexus tumors are rare intraventricular papillary neoplasms derived from choroid plexus epithelium, which account for only between 0.4-0.6% of all intracranial and 2-3% of pediatric neoplasms. Plexus papillomas outnumber choroid plexus carcinomas by a ratio of 5:1 and around 80% of choroid plexus carcinomas arise in children. Plexus tumors are most common in the lateral and fourth ventricles; while 80% of lateral ventricle tumors present in children, fourth ventricle tumors are evenly distributed in all age groups. Clinically, choroid plexus tumors tend to cause hydrocephalus and increased intracranial pressure. Histologically, choroid plexus papillomas correspond to WHO grade I, choroid plexus carcinomas to WHO grade III. Immunohistochemically, cytokeratins and vimentin are expressed by virtually all choroid plexus papillomas and most choroid plexus carcinomas while transthyretin and S-100 protein are present in 80-90% of cases, less frequently, though, in choroid plexus carcinomas. Glial fibrillary acidic protein can be found focally in about 25-55% of choroid plexus papillomas and 20% of choroid plexus carcinomas. The mean Ki67/MIB1 labeling index for choroid plexus papillomas is 1.9%, for choroid plexus carcinomas 13. 8%. Choroid plexus papillomas typically show hyperdiploidy with gains particularly on chromosomes 7, 9, 12, 15, 17, and 18 while one choroid plexus carcinoma showed rearrangements of chromosomes 7p11-12, 9q11-12, 15q22, and 19q13.4. Choroid plexus papillomas can usually be cured by surgery alone with a 5-year survival rate of up to 100% with occasional recurrences while choroid plexus carcinomas grow more rapidly and have a less favorable outcome with a 5-year survival rate of 26-40%.

Clinical and pathologic features of oligodendrogliomas in two cats

Two oligodendrogliomas in two domestic cats involved mainly the rostral brain stem, midbrain, fourth ventricle, and cerebellum. Both cats were aged neutered males presenting with clinical neurologic deficits suggestive of a brain stem lesion. Magnetic resonance imaging of both tumors demonstrated lesions with a pattern of heterogeneous contrast enhancement and multifocal lesions in one cat. Routine cerebrospinal fluid analysis was normal in one cat and suggestive of an inflammatory disease in the other. Oligodendroglioma cells were seen in cytospin preparations of cerebrospinal fluid from both cats. In each cat, the tumors occurred intraventricularly in the midbrain and fourth ventricle with aggressive intraparenchymal infiltration. There was extensive growth into the basilar subarachnoid space of the midbrain and brain stem in one cat. One tumor was well differentiated, and the other was an anaplastic subtype. Immunostaining for several myelin- and oligodendroglia-specific antigens was negative with formalin-fixed tumors and with unfixed frozen samples from one cat. In both tumors, component cells of the intratumoral vascular proliferations were positive for human von Willebrand factor VIII antigen or smooth muscle actin. Immunocytochemical reactivity for glial fibrillary acidic protein identified both reactive astrocytes and a subpopulation of minigemistocytes in both tumors. Ultrastructurally, the tumor cells were unremarkable except for their prominent desmosomal junctions and paucity of microtubules.

Spinal oligodendroglioma with diffuse arachnoidal dissemination in a Japanese Black heifer

A gelatinous focus with cystic spaces, was found in the posterior funiculus of the 2nd to 3rd lumbar levels of the spinal cord of a Japanese Black heifer, 2 years old, with clinical signs of severe dysstasia. Histopathological examination revealed that the spinal lesion consisted of multifocal and diffuse proliferation of round cells with abundant vacuolar cytoplasm and hyperchromatic nuclei. In the lesions there was a number of cystic spaces containing aggregates of small round cells. The neoplastic foci showed a honeycomb structure divided by thin blood vessels, representing typical lesions of oligodendroglioma. Diffuse and multifocal proliferation of these round cells were also recognized in the subarachnoidal space in the sacral spinal cord. Immunohistochemically, the proliferating round cells were negative for glial fibrillary acidic protein. Based on these morphological features, the case was diagnosed as lumbar spinal oligodendroglioma with diffuse arachnoidal dissemination.

A comparative immunohistochemical study of pancreatic islets in laboratory animals (rats, dogs, minipigs, nonhuman primates)

The aim of the present study was to distinguish and describe the patterns of distribution of pancreatic islets within the pancreas of four species of laboratory animals, including rats, dogs, minipigs and monkeys, and furthermore, to identify immunohistochemically various islet cell types and characterize their content. Histopathological examinations were performed on sections stained with hematoxylin and eosin (H&E) and immunostained using rabbit polyclonal antibodies (pAb) against insulin, glucagon, pancreatic polypeptide (PP), somatostatin, chromogranin A, keratin, bombesin and gastrin, or mouse monoclonal antibodies (mAb) against synaptophysin, Leu-7 and proliferating cell nuclear antigen (PCNA) in three-step rabbit immunoperoxidase (PAP) and streptavidin/peroxidase (StreptABC/HRP) reactions. Positive immunohistochemical reactions were observed in the pancreatic islets of all animal species with all antibodies, except with anti-bombesin and anti-gastrin antibodies. Our results revealed that: 1) there is species specific regional arrangement of islets in the pancreas, 2) each species presents a characteristic distribution of cells producing different hormones. 3) immunoreactivity with immunohistochemical markers varies between species and/or age. The present comparative immunohistochemical study could be helpful for answering questions which are important for understanding some of the intricate mechanisms that govern the integrated function of the endocrine pancreas.

The immunophenotypic spectrum of meningeal hemangiopericytoma: a comparison with fibrous meningioma and solitary fibrous tumor of meninges

Despite controversy regarding its histogenesis, meningeal hemangiopericytoma (HPC) is a well-defined clinicopathologic entity exhibiting high rates of recurrence and late extracranial metastasis. It must be distinguished from several benign neoplasms, particularly fibrous meningioma (FM) and solitary fibrous tumor (SFT). To determine the immunoprofile of HPC, we studied 27 meningeal examples, including 13 low-grade and 14 high-grade tumors. For comparison, 20 FMs and eight SFTs of the meninges were also evaluated. The immunotype of HPC included vimentin (85%), factor XIIIa (78%) in individual scattered cells, Leu-7 (70%), and CD34 (33%) in a weak, patchy pattern. Focal desmin and cytokeratin positivity was only occasionally encountered (20% each). The SFT shared a similar immunophenotype, except that CD34 expression (100%) was characteristically strong and diffuse. The FM characteristically expressed epithelial membrane antibody (EMA) (80%) and S-100 protein (80%); CD34 reactivity (60%) was patchy and weak. Both within and among all three tumor types, MIB-1 labeling indices varied widely. Specifically, they were unrelated to tumor grade in HPC. Significant reactivity for p53 protein was detected in 52% of HPCs, 17% of SFTs, and 5% of FMs. Meningeal HPC exhibits a distinct antigenic profile, one enabling the exclusion of other entities in nearly all cases. The rare expression of desmin or cytokeratin in HPC suggests either the occurrence of divergent differentiation or, less likely, the possibility that its distinctive morphology is but a phenotype shared by several types of meningeal sarcoma.

Congenital oligodendroglioma: a case report of a 34th-gestational week fetus with immunohistochemical study and review of the literature

A case of congenital oligodendroglioma occurring in a 34th-gestational week fetus is reported. The tumor was necrotic, hemorrhagic, and gelatinous. It covered the basal part of the brain, and almost the entire cerebellum was replaced by the tumor. The tumor cells had small, round, hyperchromatic nuclei and watery clear cytoplasm, and were arranged in a paved or alveolar pattern. Immunohistochemically, S100 protein, myelin-basic protein, neuron-specific enolase and Leu 7 were weakly positive for the cytoplasm, but glial fibrilliary acidic protein, synaptophysin, neurofilament, desmin, and vimentin were negative. Many tumor cell nuclei were positive for mutant p53 protein, and the labeling index was 85%. But there was no genetic alteration in exons 4 to 9 of p53 gene from the peripheral blood. The apoptosis index was 1.5%. Considering the p53 labeling index and the apoptosis index together, this congenital oligodendroglioma may be regarded as potentially malignant despite the benign morphological features.

Central neurocytoma: clinical, immunohistologic, and biologic findings of a human neuroglial progenitor tumor

BACKGROUND

Central neurocytomas are rare brain tumors recognized by their typical radiologic and histologic features. In general, a good prognosis is achieved by total removal. The histogenesis is still under debate, but a neuronal origin is widely assumed.

METHODS

This study presents the clinical and immunohistologic findings of five patients and the results of cell culture experiments of two patients with central neurocytoma treated surgically between 1983 and 1993.

RESULTS

The patient age at diagnosis ranged from 21 to 30 years (mean, 25 years). The male-to-female ration was 1:4. Raised intracranial pressure due to hydrocephalus was the main cause of the clinical manifestations. Total resection was achieved in two cases. Four patients received radiotherapy. One patient suffered a recurrence 1 year after surgery, requiring a second resection and radiotherapy. Follow-up studies took place between 1 and 10.5 years (mean, 7.1 years). To date, all patients are free of their tumors. Two patients suffered from permanent memory disturbances after surgery. Immunohistochemistry confirmed the neuronal nature of the tumors. Cell-culture studies, which have been carried out for the first time, demonstrated concomitant expression of neuronal (synaptophysin) and glial (GFAP) markers.

CONCLUSION

Total removal is the therapy of choice. In tumor recurrence or limited surgery (e.g. due to severe affliction of the fornical structures), radiotherapy has shown to be efficacious. The cell-culture experiments give new insight on the histogenesis of central neurocytoma, indicating that the tumor arises from an undifferentiated precursor cell with the capacity of bipotential neuroglial differentiation.

Central neurocytoma: clinico-pathological study of 5 cases and review of the literature

Five cases of central neurocytoma, confirmed by immunohistochemical and electron microscopy studies, are reported and 127 cases from the literature are reviewed. Central neurocytomas are more frequent than previously thought, and will be diagnosed with increasing frequency in the future, if intraventricular tumors with histological aspect of oligodendroglioma or ependymoma will be routinely studied by immunohistochemistry and electron microscopy. The occurrence of an intraventricular tumor with a typical MR aspect in a young patient should suggest preoperatively the diagnosis of neurocytoma. The positivity for synaptophysin and neuron specific enolase, the negativity for neurofilament protein and glial fibrillary acid protein, and the finding of elements of neuronal differentiation on electron microscopy, are the main pathological features of these tumors. Complete removal of the tumor mass without radiotherapy is the treatment of choice. The prognosis is usually favorable without recurrence.

Human neurocytoma cells in culture show characteristics of astroglial differentiation

Cultured human neurocytoma cells from two neurosurgical patients were analysed for their immunocytochemical staining patterns and growth characteristics. In both cases, the cells stained positive for glial acidic fibrillary protein (GFAP) within one day of tissue culture in medium, with and without fetal calf serum, whereas the histological tumor specimens were negative. Both cases contained cells concomitantly expressing GFAP and synaptophysin (SNP) in the primary cultures. Epidermal growth factor (EGF) was mitogenic for the cultured cells but not platelet derived growth factor alpha (PDGF AA) or nerve growth factor (NGF). It is concluded that the human neurocytomas may represent neoplasms of a pluripotent neuroglial cell which can provide an interesting model to study the determinants for human glial/neuronal differentiation in vitro.

Neuron-associated class III beta-tubulin, tau, and MAP2 in the D-283 Med cell line and in primary explants of human medulloblastoma

The D283 Med human medulloblastoma cell line and primary explants of five surgically excised medulloblastomas were cultured using a three-dimensional Gelfoam matrix system. The cultures were evaluated immunohistochemically for a series of antigenic determinants associated with neuronal or glial differentiation. Focal immunolocalization of class III beta-tubulin, microtubule-associated protein 2 (MAP2), and to a lesser degree tau, was demonstrated in all cultures. Class III beta-tubulin isotype, MAP2, and tau protein were also detected by immunoblot in Gelfoam matrix cultures, monolayer cultures, and suspension cultures of D283 Med cells. Staining for neurofilament protein epitopes was highly variable, even among different cultures derived from the same original tumour, but time-dependent changes in neurofilament protein, which may have reflected neuronal differentiation, were not consistently shown. Widespread gamma-enolase and focal synaptophysin reactivities were visualized in all cultures, but no S-antigen staining was detected. Leu 7 labelling was variably present in half of the cultures of D283 Med cells, but was more abundant in explants derived from four of the five original tumours. Vimentin was consistently found in D283 Med cultures at all time points. No immunoreactivity for glial fibrillary acidic protein was detected in the D283 Med cell line. Conversely, staining for this protein was demonstrated in scattered astrocytic cells in the surgical specimens of all five medulloblastomas. Concomitant with increased time in culture, three of the primary tumours displayed increased numbers of glial fibrillary acidic protein-positive cells when cultured in the Gelfoam system, but the other two tumours had a minimal astrocytic component.(ABSTRACT TRUNCATED AT 250 WORDS)

Central neurocytoma: its differentiation from intraventricular oligodendroglioma

Two patients with intraventricular tumours are presented. Both had similar features on light microscopic examination. On the basis of the specific immunohistochemical staining patterns and the ultrastructural findings, one was diagnosed as a central neurocytoma while the other was diagnosed as an intraventricular oligodendroglioma. The possibility of central neurocytoma should be considered in all young patients including children presenting with an intraventricular lesion. Definitive diagnosis requires electron microscopic and immunohistochemical studies.

Expression of oligodendroglia and Schwann cell markers in human nervous system tumors. An immunomorphological study and western blot analysis

Sixty tumors of the central and peripheral nervous system and seven brain metastases of extracranial carcinomas were examined using the peroxidase-antiperoxidase method to study the expression of myelin basic protein (MBP), myelin-associated glycoprotein (MAG) and the HNK-1/Leu-7 epitope. The immunocytochemical findings were compared with and correlated to Western blot results. None of the tumor types, including oligodendrogliomas, neurinomas and neurofibromas, expressed MAG and MBP, whereas myelin sheaths and their remnants within the tumors yielded specific immunoreactions. In contrast, the HNK-1/Leu-7 antibodies labelled the majority of the tumors tested including oligodendrogliomas and Schwann cell tumors. As demonstrated by Western blot experiments the HNK-1/anti-Leu-7 antibodies exhibited positive reactions with diverse polypeptides both in tumors and in non-neoplastic brain tissue at positions not corresponding to MAG. This suggests that the epitope recognized by HNK-1/Leu-7 antibodies is shared by a variety of unrelated proteins in normal and neoplastic tissues. Our results strongly indicate the absence of detectable amounts of MBP and MAG in oligodendrogliomas and Schwann cell tumors. The immunomorphological and immunochemical findings clearly showed the wide distribution of the HNK-1 epitope within different tumor types of the central and peripheral nervous system. In conclusion, the data demonstrate that specific cell markers for human oligodendrogliomas and Schwann cell tumors are still lacking.

Heterotransplantation of a human oligoastrocytoma into nude mice: difference in tumour growth between males and females

A human oligodendroglial tumour cell line was established in the nude mouse from a mixed oligoastrocytoma. This cell line was identified by immunoperoxidase screening for glial fibrillary acid protein (GFAP) and Leu-7, by electron microscopy, by its growth behaviour, and by radioreceptor assays for oestrogen, progestogen and androgen. At the first heterotransplantation, the tumour grew in the female but not in the male mice. GFAP-positive cells were much less abundant than in the initial tumour, although Leu-7 positive cells were plentiful. Growth curves were biphasic, and the tumours contained both oestrogen and androgen receptors. After three successive heterotransplantations in female mice, GFAP-negative, Leu-7-positive tumours with the cytological features of an oligodendroglioma were obtained. In contrast to those of the first heterotransplantation, the growth curves showed a longer latency and a single growth phase. The tumours contained both progestogen and androgen receptors but lacked oestrogen receptor. The 5th heterotransplantation in male mice exhibited rapid growth, similar to the three previous heterotransplantations in the female mice. The growth observed solely in the female mice at the first heterotransplantation was thought to derive from the hormonal status of the host. The presence of hormone receptors in the tumours at the first heterotransplantation lent support to this idea. There was no further influence of the sex of the host on tumour growth once the oligodendroglial line was established. The establishment and the development of oligodendrocytes may result from differentiation of transitory cells intermediate between astrocytes and oligodendrocytes. The effect of host-sex on the development of oligodendrocytes points to a new facet of the differentiation of CNS glial cells.

Expression of the neu oncogene under the transcriptional control of the myelin basic protein gene in transgenic mice: generation of transformed glial cells

We have taken a transgenic approach in an effort to specifically transform oligodendrocytes, the myelinating glial cells of the central nervous system (CNS). Transgenic mice were generated with a DNA construct that contained the activated neu oncogene under the transcriptional control of the myelin basic protein (MBP) gene. The MBP/c-neu transgenic animals have experienced a low incidence of brain tumors that express molecular markers specific to oligodendrocytes, providing a mouse model to study the formation and progression of oligodendrocyte tumors. A tumor from a transgenic animal has been dispersed in culture, and transformed cells that express properties of oligodendrocytes and astrocytes have been maintained. The degree to which these cells express phenotypic characteristic of oligodendrocytes or astrocytes is influenced by culture conditions. These transformed cells should serve as a valuable resource with which to study various molecular and biochemical aspects of the myelination process, as well as the lineage interrelationship of CNS glial cells.

Infratentorial ependymomas of childhood. Correlation between histological features, immunohistological phenotype, silver nucleolar organizer region staining values and post-operative survival in 16 cases

We have examined pathological criteria in 16 cases of infratentorial ependymomas of childhood using a conventional histological approach, with immunohistochemistry and silver nucleolar organizer region staining (AgNORs). We have found that some of these criteria are of prognostic value. The following histological features were evaluated in each case: cellular density, cellular or nuclear pleiomorphism, mitosis, focal necrosis, endothelial proliferation and complete loss of differentiation. The expression of the following antigens was also studied: epithelial membrane antigen (EMA), human natural killer (HNK1), glial fibrillary acidic protein (GFAP) and vimentin. Only three histological criteria have been retained as indicative of bad prognosis, i.e., high mitotic index, a large amount of necrosis and complete loss of differentiation. These criteria distinguish ependymomas from anaplastic ependymomas. GFAP was expressed in all tumors while other antigens were more variable. In addition tumors expressing large amounts of GFAP were statistically associated with a better prognosis. Increased vimentin expression associated with a decrease of GFAP immunoreactivity correlated with anaplasia and short survival. EMA was not directly correlated with postoperative survival but may be considered as a further prognostic factor. Finally AgNORs values were not statistically correlated with postoperative survival.

Central neurocytoma: immunohistochemical and ultrastructural study

Eight cases of central neurocytomas were studied by immunohistochemistry and electron microscopy. Seven tumors were located in the lateral ventricles and one in the subependymal region. All but one patient had a favorable postoperative course. The tumors were composed of small uniform cells possessing amitotic round nuclei with frequent perinuclear halos, a few Homer Wright rosettes and no ganglion cells; an appearance resembling that of oligodendroglioma. Immunohistochemical studies disclosed neuron-specific enolase and Leu-7 positivity in all tumors, S-100 protein-positive cells were found in six, while glial fibrillary acidic protein--and vimentin-positive cells were confined to the blood vessels. Myelin basic protein as well as neurofilament were not detected in the tumors. Synaptophysin-positive areas were seen in one tumor. Ultrastructural examination showed distinctive neuronal tumor cells which had a cytoplasm with sparse dense-core vesicles and thin cell processes containing parallel microtubules. They were classified into three different types of tumor cells according to the extent of differentiation. The most consistent finding for histological diagnosis was the presence of typical or abortive synapses with clear and dense-core vesicles. Additionally, synaptophysin may be a specific marker for some central neurocytomas.

Intraventricular neurocytoma, a recently recognized pathological entity: report of two cases and review of the literature

Neurocytoma has only recently been recognized as a distinct pathological entity. Previously a rare tumor, it is now being recognized with increasing frequency. It typically presents in an intraventricular location in young adults. Many neurocytomas were originally diagnosed by light microscopy as oligodendrogliomas. More recently they have been shown to have ultrastructural and immunohistochemical features of neuronal differentiation. This paper presents two cases of intraventricular neurocytomas and reviews the recent literature.

Immunohistochemical characterization of rat central and peripheral nerve tumors induced by ethylnitrosourea

Ethylnitrosourea-induced central and peripheral nerve tumors in Sprague-Dawley rats were tested for GFAP (Glial Fibrillary Acidic Protein), S-100 protein, NSE (Neuron Specific Enolase) and Anti-Leu 7 (HNK-1) immunoreactivity utilizing the ABC method (avidin-biotin-complex) for GFAP, S-100 protein and NSE, and the PAP method (peroxidase-antiperoxidase) for Anti-Leu 7. Peripheral nerve neurinomas were consistently positive for S-100 protein and consistently negative for GFAP and Anti-Leu 7. Neurinomas would occasionally exhibit positive staining for NSE (2 of 55 tumors). The staining intensity for S-100 protein varied from strongly positive in differentiated neurinomas to weakly positive in anaplastic tumors. Neoplastic and reactive astrocytes exhibited positive staining for both S-100 protein and GFAP. Variation in the GFAP staining intensity of glial tumors correlated with the degree of differentiation as anaplastic tumors did not stain with the same intensity as their more differentiated counterparts. Oligodendrogliomas exhibited occasional immunoreactivity to S-100 protein (3 of 36 tumors). NSE reactivity in oligodendrogliomas was rarely observed (1 tumor in 36) and immunoreactivity against GFAP or Anti-Leu 7 was consistently absent. Anti-Leu 7 and NSE proved to be of little value in the classification of ENU-induced neural tumors.

Immunohistological investigation of mononuclear cell infiltrates in meningiomas

Immunohistochemical analysis of inflammatory cell density and infiltrate subpopulations in 42 meningiomas was performed. Evaluation of infiltrating cell density was carried out by cell counting. Meningothelial and fibroblastic meningiomas contained an average of 3% mononuclear cells; the few lymphocytes were localized in the perivascular spaces. In subtypes with cellular atypies and recurrent tumors, the inflammatory cells increased up to 9%. We found small mononuclear cell clusters in the tumor parenchyma in addition to the perivascular infiltrates. Marked degrees of infiltration were found in anaplastic meningiomas (average 13.5% of total cells). The lymphocytic infiltrates were localized in multilayered perivascular cuffings and intraparenchymal cell clusters. The composition of the infiltrates, i.e., predominantly a mixed staining of cytotoxic/suppressor and helper cell phenotypes, did not vary in the different subtypes. We conclude: (1) that inflammatory infiltration is more frequent and denser in malignant than in benign meningiomas; and (2) that the tumor defense mechanisms in meningiomas are mediated particularly by T cell mediated immunity.

Clear cell sarcoma. An immunohistochemical and ultrastructural study

The histogenesis of clear cell sarcoma was investigated by immunohistochemical examination of five tumors (two melanotic and three amelanotic) and electron microscopic examination of two of these tumors (one melanotic and one amelanotic). Melanin production was observed histologically in two of the tumors. The cytoplasm of cells in both types of tumor contained various numbers of melanosomes. Melanoma-specific antibody (HMB-45), anti-S-100 protein, and anti-vimentin antibodies gave positive reactions in four tumors, while all tumors showed Leu-7 immunoreactivity. No cytokeratin or epithelial membrane antigen (EMA) was detected immunohistochemically in any tumor. The immunoreactivity of this type of tumor with HMB-45 antibody strongly suggests melanocytic differentiation rather than schwannian or synovial differentiation. The reaction of the cells of one tumor with only Leu-7 indicates the existence of undifferentiated clear cell sarcoma of neuroectodermal origin that does not show definite melanocytic differentiation.

The identification of cells containing JC papovavirus DNA in progressive multifocal leukoencephalopathy by combined in situ hybridization and immunocytochemistry

A double-labelling technique combining in situ hybridization and immunocytochemistry is described which was used to characterize cells in the central nervous system containing JC virus DNA in formalin-fixed, paraffin-embedded tissues from four cases of progressive multifocal leukoencephalopathy. All four cases showed positive nuclear labelling for JC virus in both oligodendrocytes and astrocytes. The latter gave a strongly positive cytoplasmic staining reaction using antibodies to glial fibrillary acidic protein and vimentin. No nuclear labelling of neurones or endothelial cells was noted. The results confirm previous suggestions that glia are the main cells infected by JC virus in this disorder and show that the distribution of viral DNA in the brain is more extensive than suggested by routine microscopy alone. In situ hybridization for JC virus may be useful in confirming the diagnosis of progressive multifocal leukoencephalopathy in both surgical biopsies and post-mortem brain tissue.

Immunohistochemistry of retinoblastoma. A review

Various studies which relate to the immunohistochemical identification of neuronal, glial, carbohydrate and nucleic acid associated antigens in retinoblastoma will be reviewed. The majority of these studies appear to support the concept that retinoblastomas arise, in situ, from neuron committed cells and in some cases specifically into photoreceptor-like cells. In selected cases, however, glial cell differentiation may be a feature of the tumor. In addition, the molecular biology of the retinoblastoma gene and the immunohistochemical characterization of its gene product will be discussed.

"Chordoid" meningeal tumors in young individuals with peritumoral lymphoplasmacellular infiltrates causing systemic manifestations of the Castleman syndrome. A report of seven cases

Seven young patients ranging in age from 8 to 19 years had surgically removed meningeal neoplasms with a peculiar myxoid-chordoid pattern. The tumors were surrounded by massive polyclonal lymphoplasmacellular infiltrates with follicles and germinal centers. The patients preoperatively manifested iron-resistant hypochromic microcytic anemia, and one of them had dysgammaglobulinemia and stunted growth. After the masses were removed, the blood picture of the patients normalized, and the adolescent with retarded somatic development resumed normal growth, but two patients developed local recurrence with identical histology and again became anemic. It appears that the peritumoral lymphoplasmacellular infiltrates, which in these instances may be regarded as reactive rather than primary cell proliferations, nevertheless brought about the type of systemic manifestations known as the Castleman syndrome, characteristically seen in patients with angiofollicular lymphoid hyperplasia (hamartoma) of soft tissues, or Castleman's tumor. In one of our patients the inflammatory infiltrate extended far into the surroundings of the meningioma, resulting in the erroneous initial diagnosis of "encephalitis" from a needle biopsy of the brain near the tumor.

Primary central nervous system lymphoma

Primary lymphoma of the central nervous system (CNS), including reticulum cell sarcoma, microglioma, and histiocytic lymphoma, represents less than 1% of all primary brain tumors. In the last 10 years, this tumor has tripled in frequency in the nonimmunosuppressed population. By 1991, the tumor will be the most common neurological neoplasm by virtue of the increase in sporadic occurrence and in the acquired immunodeficiency syndrome (AIDS) population. Three percent of AIDS patients will develop this tumor either prior to AIDS diagnosis or during their subsequent course. In addition to acquired immunosuppression, patients with inherited disorders (such as Wiskott-Aldrich syndrome, severe combined immunodeficiency, and X-linked immunodeficiency) and other acquired disorders of the immune system are predisposed to the development of CNS lymphoma. Immunological studies have suggested a role for Epstein-Barr virus in the production of this tumor. Although subtypes exist, non-Hodgkin's lymphoma of the CNS most commonly consists of histiocytic cells or large immunoblastic cells bearing B cell surface markers in close proximity to the lateral and third ventricles. Sixty percent of these deposits are multiple, and subarachnoid invasion is seen in one-quarter of patients. Vitreous involvement of the eye occurring prior to and during the course of CNS lymphoma has been noted in up to 25% of patients. The involvement of multiple areas of the neuraxis, the eye, and multiple intracranial sites often occurs in the absence of obvious systemic lymphoma. Therapeutic trials of brain radiation therapy are associated with median survivals of less than 1 year. Uniform complete responses of intracranial deposits are recorded following chemotherapy with high-dose intravenous methotrexate, CHOP (cyclophosphamide, hydroxydaunomycin/doxorubicin, Oncovin (vincristine), and prednisone), high-dose cytosine arabinoside, and intra-arterial methotrexate with barrier modification.

Reactivity of circulating antineuronal antibodies (CANA) on peripheral nervous system structures

The appearance of circulating antineuronal antibodies (CANA) in patients with malignant tumors has been correlated with the occurrence of paraneoplastic neurological syndromes. However, the effect of CANA on the peripheral nervous system is poorly understood. The reactivity of sera from CANA-positive and -negative patients were investigated on cryostat sections of peripheral nerves and skeletal muscle, and on nerve tease-fiber preparations. Only CANA-positive sera showed staining of Schwann cell nuclei on cryostat sections, whereas nerve tease-fiber preparations and sections of skeletal muscle remained negative. Positive direct immunofluorescence of small cell lung cancer (SCLS) cells was confined to CANA-positive patients only. These findings suggest the existence of a common antigen between SCLC and Schwann cells.

Immunohistochemical characterization of human retinoblastomas in situ with multiple markers

We studied paraffin-embedded specimens from 18 surgically enucleated eyes with retinoblastoma by peroxidase-antiperoxidase immunohistochemistry with antibodies against glial fibrillary acidic protein, S-100 protein, Leu 7 epitopes, neuron-specific enolase, the 200-kilodalton subunit of the neurofilament triplet polypeptide, and retinal S-antigen. We found that (1) glial fibrillary acidic protein, S-100 protein, and Leu 7 epitopes were detected only in well-differentiated glial cells that were interpreted as reactive and not neoplastic, (2) undifferentiated neoplastic cells expressed both neuron-specific enolase and retinal S-antigen immunoreactivity, and (3) differentiated cells forming Flexner-Wintersteiner rosettes were found to express neuron-specific enolase, retinal S-antigen, and, occasionally, neurofilament protein. These results support the view that retinoblastomas are composed of neuron-committed cells and favor the origin of these tumors from photoreceptor progenitor cells. We did not find any morphologic or immunohistochemical evidence of glial differentiation from tumor cells that would support the concept that retinoblastoma arises from a primitive neuroectodermal cell capable of divergent differentiation along neuronal and glial lines.

Anti-Leu 7 immunoreactivity with human tumours: its value in the diagnosis of prostatic adenocarcinoma

The reactivity of the anti-Leu 7 monoclonal antibody (Leu 7) was tested on 83 human tumours and on non-neoplastic prostatic, hepatic and pancreatic tissues. A four-step peroxidase-anti-peroxidase method was used on paraffin embedded tissues and we observed strong cytoplasmic positivity in all 19 primary prostatic tumours, in two metastatic, poorly differentiated prostatic adenocarcinomas, and in normal and hypertrophic prostatic epithelium. All the primary prostatic tumours also stained positively for prostate-specific antigen and for prostatic acid phosphatase using polyclonal antisera. The degree of positivity for these antigens varied from case to case. Adenocarcinomas arising from the gastrointestinal tract, pancreas and gallbladder were anti-Leu 7 negative. Focal Leu 7 positivity, largely confined to cell membranes, was observed in some ovarian, endometrial, renal, lung and breast adenocarcinomas. These tumours, as well as some of the gastrointestinal, hepatic and pancreatic tumours, also showed focal cytoplasmic positivity for prostate-specific antigen and prostatic acid phosphatase. Our findings suggest that the anti-Leu 7 monoclonal antibody is a marker that may facilitate the detection of metastatic prostatic adenocarcinoma, especially when used in conjunction with staining for prostate-specific antigen.

Differential expression of glial- and neuronal-associated antigens in human tumors of the central and peripheral nervous system

The immunoreactivity of a panel of poly- and monoclonal antibodies raised against different glial and neuronal antigens was investigated in paraffin-embedded specimens of 116 human tumors of the central and peripheral nervous system. We used antibodies against the HNK-1 epitope, which is shared between natural killer cells and the nervous system, glial fibrillary acidic protein (GFAP), vimentin, neurofilaments, S-100 protein, neuron-specific enolase (NSE) and myelin basic protein (MBP). HNK-1 immunoreactivity was detectable in nearly all neuroectodermal tumors. Especially in those derived from the neuroepithelium, which include the various types of gliomas, we observed a strong staining with this antibody. The only exceptions were the choroid plexus papillomas and individual ependymomas. In tumors derived from the neural crest HNK-1 reactivity was more variable and less intense. In other tumors of the nervous system HNK-1 was not detectable, except for two out of four malignant lymphomas. In addition to its reactivity with human lymphocytes HNK-1, therefore, seems to be a useful 'marker' for neurogenic tumors in general. GFAP expression was prominent in all astrocytomas and the astrocytic cells within mixed gliomas and gangliogliomas. Immunoreactivity was more variable in glioblastomas and ependymomas, while only isolated GFAP-positive cells were present in oligodendrogliomas, medulloblastomas, one plexus papilloma, and some neurinomas. Vimentin immunoreactivity was found in tumor cells of nearly all tumors of the central nervous system with the exception of oligodendrogliomas, most plexus papillomas, neuronal tumors and most medulloblastomas.

Expression of the HNK-1 carbohydrate epitope in human retina and retinoblastoma. An immunohistochemical study with the anti-Leu-7 monoclonal antibody

Fifty formalin-fixed and paraffin-embedded retinoblastoma specimens and five normal human eyes were studied with the monoclonal anti-Leu-7 antibody, directed against the HNK-1 carbohydrate epitope that is shared by human natural killer cells and many neuronal, glial and neuroectodermal cells. The laboratory method was a sensitive immunohistochemical staining procedure, and neuroectodermal tumours that usually express this epitope were used as positive controls. In the human retina, Müller cell membranes were positively stained, but additional staining of neuronal cells was not excluded at the light microscopical level. A positive cytoplasmic reaction was also seen in ciliary and retinal pigment epithelial cells. All but one intraocular retinoblastomata studied contained cells staining positively for the HNK-1 epitope, but these cells were probably not neoplastic. Although positive reaction has previously been reported in three retinoblastomata, the present results suggest that positive cells are derived from entrapped and infiltrated retina. Staining of adjacent sections against leukocyte common antigen suggested that the positively staining cells were not natural killer cells.

Non-specific binding of mouse myeloma IgM immunoglobulins by human myelin sheaths and astrocytes. A potential complication of nervous system immunoperoxidase histochemistry

The immunoreactivity of purified mouse myeloma IgM immunoglobulins (mouse IgM) to human myelin sheaths and astroglial cells was evaluated with the peroxidase-antiperoxidase method on paraffin-embedded tissues from human gliomas and areas of multiple sclerosis, and from normal human cerebrum, spinal cord and spinal nerve roots. The mouse IgM reacted positively with central and peripheral myelin sheaths and, as shown independently by others, with the cytoplasm of neoplastic and reactive astroglia. Parallel immunostaining of successive sections with an anti-glial fibrillary acidic protein (GFAP) serum and/or the anti-Leu 7 monoclonal antibody was of considerable assistance in identifying the immunoreactive elements and in distinguishing specific from non-specific immunostaining of myelin sheaths and astroglia. Pretreatment with normal human serum inhibited the non-specific binding by mouse IgM without altering GFAP and Leu 7 reactivities. The non-specific binding of mouse IgM to human myelin sheaths and astroglia can therefore be overcome, and the specificity of mouse IgM monoclonal antibodies retained, by the parallel immunostaining of successive sections with mouse IgM. If non-specific binding by mouse IgM is found to occur, it can then be inhibited by preincubation with normal human serum without loss of specific antigenicity.

Immunohistochemical characterization of oligodendrogliomas: an analysis of multiple markers

Twenty-eight oligodendrogliomas and seven oligoastrocytomas were immunotested by the peroxidase-antiperoxidase (PAP) method with antiglial fibrillary acidic protein (GFAP) serum, anti-Leu 7 monoclonal antibody (Mab), anti-myelin-associated glycoprotein (MAG) Mab, anti-myelin basic protein (MBP) serum, anti-carbonic anhydrase C (CA C) serum and anti-neuron-specific enolase (NSE) serum. The immunoreactivity of their vascular pattern was studied with Ulex europaeus type I lectin (UEA I). According to their morphology and distribution GFAP-positive cells were respectively interpreted as reactive astrocytes, neoplastic astrocytes and neoplastic oligodendrocytes. Reactive astrocytes were found in the tumor, around the tumor and surrounding the supporting blood vessels. Neoplastic astrocytes were mainly found in the oligoastrocytomas and usually closely intermingled with neoplastic oligodendrocytes. GFAP-positive neoplastic oligodendrocytes were found in the typical oligodendrogliomatous areas. They had central nuclei and GFA positivity was mainly found in the perinuclear cytoplasm. They correspond to the "gliofibrillary oligodendrocytes" described by Herpers and Budka. Of the oligodendrogliomas 91% displayed Leu 7 positivity, but anti-Leu 7 cannot be considered as a specific marker for oligodendrogliomas since other neuroepithelial tumors have been reported to react with this antibody. MAG-, CA C- and NSE-positivities were found in a number of tumor cells in a few oligodendrogliomas. All the tumor cells were MBP-negative, but myelin sheaths and fragments of myelin in the infiltrated white matter were clearly demonstrated by this antiserum. UEA I strikingly demonstrated the vascular pattern of the tumors, and its usefulness as a discriminating marker for the supportive endothelial cells was confirmed.