Short-term post-grafting morphological alterations of glia from an adult brain transplant

Fragments of corpus callosum from adult rabbit have been implanted into the brain of newborn mice. Previous studies had shown that under such conditions transplant-derived astroglial cells differentiate in the host and survive for at least 2 months. The present study was devised to clarify the fate of the differentiated astrocytes present in the adult transplant by using combined ultrastructural and immunohistochemical approaches. These mature cells are shown to degenerate and die within 2 days after the implantation. Therefore, we suggest that stem cells present in adult tissue would account for the surviving population of transplant-derived glial cells.

An immunohistochemical study of neuropeptides and neuronal cytoskeletal proteins in the neuroepithelial component of a spontaneous murine ovarian teratoma. Primitive neuroepithelium displays immunoreactivity for neuropeptides and neuron-associated beta-tubulin isotype

Approximately one third of the female mice of the LTXBO strain develop spontaneous ovarian teratomas. These tumors contain a large neuroepithelial component, which includes primitive neural structures resembling embryonic neural tubes (medulloepithelial rosettes), ependymoblastic and ependymal rosettes, neuroblasts, mature ganglionic neurons, myelinated neurites, and astrocytes. The purpose of this study was to characterize these tumors according to the immunohistochemical location of some well-characterized trophic and regulatory neuropeptides and neurotransmitters, several neuronal-associated cytoskeletal proteins, and other proteins indicative of neuronal and glial differentiation. Medulloepithelial rosettes showed focal serotonin-like, opioid peptide-like and gamma-amino butyric acid-like immunoreactivity, and displayed immunostaining for the neuron-associated class III beta-tubulin isotype. The mature ganglion cells were also immunoreactive for these markers, and, in addition, for somatostatin, cholecystokinin, bombesin, glucagon, vasoactive intestinal peptide, and neuropeptide Y. Mature ganglion cells were also immunoreactive for proteins associated with the neuronal cytoskeleton (including microtubule-associated proteins, MAP2 and tau, and higher molecular weight phosphorylated and non-phosphorylated neurofilament subunits), neuron-specific enolase, and synaptophysin. Undifferentiated stem cells, ependymoblastic and ependymal rosettes, and astroglia all stained with a monoclonal antibody that recognizes all mammalian beta-tubulin isotypes, but did not react with antibodies to neuronal-associated cytoskeletal proteins or neuropeptides. Neuropeptide-like immunoreactivity and demonstration of the class III beta-tubulin isotype indicate early neuronal commitment in neoplastic primitive neuroepithelium. These patterns of immunoreactivity closely follow those encountered in the normal neurocytogenesis of the mammalian and avian forebrain, and increase the precision with which the early stages of progressive neuroepithelial differentiation can be analyzed in human embryonal tumors of the CNS.

Thallium-201 uptake relates to membrane potential and potassium permeability in human glioma cells

The mechanism for 201Tl+ uptake was studied in cultured human glioma cell lines. Ouabain (1 mM) decreased the uptake at steady-state to 60%, but the rate of uptake was faster in the presence of ouabain. Addition of non-radioactive Tl+ (to a K+-free medium) decreased the uptake, but much less than expected for a system limited by the number of transport sites. Changes in K+ concentration of incubation medium affected the 201Tl+ uptake as predicted by the electrochemical equilibrium (Nernst equation). Using the uptake in isotonic KCl as a reference for membrane potential (0 mV), the calculated membrane potential was -75 mV in a medium with 3.0 mM K+. The Tl+-flux constants and the membrane permeabilities for Tl+ and K+ were calculated from the rate of uptake and from wash-out experiments. This is a new method for membrane potential and permeability studies in cell populations. The mechanism for 201Tl+ uptake is relevant for the clinical interpretation of 201Tl+ scintigraphy.

Cerebellar desmoplastic medulloblastomas. A further immunohistochemical characterization of the reticulin-free pale islands

We studied by immunohistochemistry the features of differentiation in 24 desmoplastic and 16 classic medulloblastomas (median patient ages, 18 and 6.5 years, respectively) with the use of a panel of cytoskeletal and synaptosomal markers. A distinctive pattern of immunoreactivity with a series of monoclonal antibodies (Mabs) was documented in the polar tumor cells forming the reticulin-free pale islands of the desmoplastic variant, denoting overt neuritogenesis. These comprised the following: (1) Mab Tp-NFP1A3 recognizing an epitope in the high-molecular-weight (Mr) isoform of neurofilament protein; (2) Mab AP18 to the high-Mr microtubule-associated protein 2; (3) Mab TUJ1 recognizing the class III beta-tubulin isotype (human h beta 4); and (4) Mab SY38 to synaptophysin. Immunoblot analysis confirmed the expression of h beta 4 in three medulloblastomas, yielding strong single bands in two desmoplastic medulloblastomas and a considerably weaker band in one classic medulloblastoma. Glial fibrillary acidic protein-positive tumor cells frequently formed an integral component of the pale islands. Oligodendrogliallike areas in one classic and in three desmoplastic medulloblastomas were immunopositive for the Mabs to synaptophysin, microtubule-associated protein 2, and h beta 4, indicating a neuroblastic nature. We propose that the reticulin-free structures of desmoplastic medulloblastomas constitute neoplastic foci with features of predominantly neuronal and, to a lesser degree, astroglial differentiation.

An immunohistochemical characterization of the primitive and maturing neuroepithelial components in the OTT-6050 transplantable mouse teratoma

The neuroepithelial component of the OTT-6050 mouse teratoma has previously been characterized as an experimental system for the study of differentiation and cytologic maturation in embryonal tumours of the human central nervous system. A number of transplantable tumours composed of primitive stem cells and of a neuroepithelial component displaying a spectrum of differentiation were previously produced by centrifugal elutriation of the dissociated OTT-6050 teratoma. These tumours have provided a reproducible cell population that has permitted the study of both the early and later stages of neoplastic neurocytogenesis. The purpose of the present study was to detect, by immunohistochemistry, the earliest stages of neurocytogenesis in these tumours as shown by the expression of neuron-associated microtubule proteins. This was correlated to the appearance and localization of other markers associated with neuronal and glial differentiation. The primitive neuroepithelial structures resembling neural tubes (medulloepithelial rosettes) contained single or small groups of cells which reacted with the monoclonal antibody TUJ1, specific for the neuron-associated class III beta-tubulin isotype. Immature neuroblasts and maturing polar neurons also showed immunoreactivity with TUJ1, whereas reactivity for microtubule-associated protein 2 (MAP2), tau, the 200 kilodalton isoform of neurofilament protein, neuron-specific enolase and synaptophysin was primarily seen in maturing neurons. By comparison, both medulloepithelial and ependymoblastic rosettes, neuroblasts and glial cells were immunopositive with monoclonal antibody TU27, which defines an antigenic site shared by most mammalian beta-tubulin isotypes. Astroglia were reactive with antisera to glial fibrillary acidic and S-100 proteins, but not with monoclonal antibody (MAb) TUJ1, or with MAbs to the other neuron-associated cytoskeletal proteins, MAP2, tau and the 200 kilodalton subunit of neurofilament protein. Our findings suggest that (1) expression of the class III beta-tubulin isotype is an early event during neoplastic neurocytogenesis, (2) this isotype is subsequently preserved in maturing neuronal populations, and (3) it is not present at detectable levels in stem cells or glial cells. The observation that morphologically undifferentiated neuroepithelial cells express a neuron-associated beta-tubulin isotype signifies the value of examining tubulin isotype expression in the characterization of normal and neoplastic neuroepithelial differentiation.

Ganglioside composition in human meningiomas

The ganglioside composition in meningioma specimens from 20 patients was analyzed to find potential meningioma-associated structures. The characterization was performed by immunological staining with specific monoclonal antibodies to ganglioside antigens and fast atom bombardment-mass spectrometry. The major gangliosides were GM3 and GD3, and most of the meningioma specimens could be divided into a "GM3-rich" or a "GD3-rich" group. Gangliosides of the gangliotetraose series were represented by GM1, GD1a, GD1b, and GT1b, which were found in minor amounts in all the specimens. The ratios of GM1/GD1a and GD1a/GD1b differed from that in normal brain, and therefore existence of this series could not be explained by contamination with brain material. Ganglioside 3'-isoLM1, found in human malignant glioma, could not be detected in any meningioma specimen.

Relationship of the demonstration of intermediate filament protein to kinetics of three human neuroepithelial tumor cell lines. Lack of neural-related proteins in most cells in S phase: a double-labeled immunohistochemical study on matrix cultures

The immunocytochemical demonstration of intermediate filament proteins in three human neuroepithelial tumor cell lines maintained in vitro on a three-dimensional matrix was correlated with the proportion of cells in S phase. The cell lines of a medulloblastoma (D283 Med), a retinoblastoma (WERI-Rb1), and an astrocytic glioma (U-251 MG) were cultured in an organ culture system, pulse-fed with bromodeoxyuridine, and double-labeled by immunoperoxidase and by the avidin-biotin peroxidase complex method for bromodeoxyuridine and for intermediate filament proteins [each triplet of neurofilament proteins, as well as vimentin and glial fibrillary acidic (GFA) protein] using eight different antibodies. The average percentages of bromodeoxyuridine-labeled cells for the D283 Med, WERI-Rb1, and U-251 MG lines were respectively, 25, 32, and 12% 30 minutes after pulse labeling. In the D283 Med line, 15- greater than 95% of the cells were positive for each neurofilament protein, and 80% of the cells were positive for vimentin; less than 10% of the cells in S phase were positive with each of the five antineurofilament protein monoclonal antibodies (Mabs), but 20% of the vimentin-positive cells were in S phase. In the WERI-Rb1 line, 44 and greater than 96% of the cells were positive for the high-molecular-weight neurofilament subunit and high- and middle-molecular-weight neurofilament subunits proteins, respectively, but only 5% of the high-molecular-weight neurofilament positive cells were in S phase. In the U-251 MG line, 37 and 98% of the cells were positive for GFA protein and vimentin, respectively; only 3% of the GFA protein-positive cells, but 13% of the vimentin-positive cells, were in S phase. The results indicate that, when maintained in a matrix culture system, most cells in S phase in these lines lack markers of neural differentiation.

Implantation of rabbit embryo brain fragments into newborn mice: integration and survival of xenogeneic astrocytes

Brain fragments containing embryonic rabbit glia were implanted into the brains of newborn mice. The hosts developed an astroglial reaction around the transplants and along the needle tracks. Transplant-derived astrocytes were identified in the operated brain by their expression of rabbit GFAP. During the first few days post-implantation (PI) glial cells were exchanged between the transplant and the host. Less than 3 to 5 days PI, the transplant was extensively invaded by host astrocytes. Xenogeneic astroglial cells were first detected 10 days PI in the immediate proximity of the transplant. At 2 to 11 weeks, they could be detected either close to or at distance from the point of implantation. Most often, transplant-derived astrocytes presented a morphology similar to that of neighboring host astrocytes. Xenogeneic glial cells were found to participate in various types of astroglial features: sub-pial, pericapillary, fibrous, and protoplasmic. This morphological integration suggests that they are physiologically integrated, at least to a certain degree, in the host tissue. In spite of their integration into the host, xenogeneic astrocytes disappear after 3 months without signs of an inflammatory reaction.

Positron emission tomography compared with magnetic resonance imaging and computed tomography in supratentorial gliomas using multiple stereotactic biopsies as reference

Ten patients with findings at computed tomography (CT) suggesting intracranial supratentorial glioma were investigated to compare the diagnostic efficacy of this technique with that of positron emission tomography (PET) using 11C-methionine and examinations with magnetic resonance (MR). The findings were related to histopathologic examination of serial stereotactic biopsies, which were guided by the appearance of the lesions on PET examination. To obtain corresponding slice orientation with the different examination techniques, an individually shaped helmet fixation was used. However, in 3 cases this fixation device could not be used for MR. Histopathologic diagnosis, obtained in all cases from multiple target stereotactic biopsies, included glioma in 9 patients and reactive gliosis in one case. A detailed comparison of the three imaging techniques and the findings at stereotactic biopsies was possible in 7 patients, while in 3 patients comparison with MR was less exact due to the patient's refusal to wear the helmet during this examination. MR was the most accurate method for outlining the total extent of a lesion, i.e. the tumor and the edema surrounding it. Four lesions had homogeneous signal characteristics and in 6 lesions two (or more) compartments could be distinguished with MR. In 5 cases the MR findings were in complete agreement with the histopathologic findings. However, a thorough correlation between signal characteristics and histology was not possible. Using PET the occurrence and the extent of tumor tissue was correctly predicted in 7 patients. The PET was normal in one case. Findings at CT were in agreement with the histopathologic diagnosis in 5 patients. MR was the most sensitive method for the detection of lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Mitotic recombination of chromosome 17 in astrocytomas

Allelic combinations at seven loci on human chromosome 17 defined by restriction fragment length polymorphisms were determined in tumor and normal tissues from 35 patients with gliomas. Loss of constitutional heterozygosity at one or more of these loci was observed in 8 of the 24 tumors displaying astrocytic differentiation and in the single primitive neuroectodermal tumor examined. The astrocytomas showing these losses included examples of each adult malignancy grade of the disease, including glioblastoma (malignancy grade IV), and seven of them demonstrated concurrent maintenance of heterozygosity for at least one chromosome 17 locus. Determination of allele dosage together with the genotypic data indicated that the tumor chromosomes 17 were derived by mitotic recombination in 7 of the 9 cases with shared homozygosity of the region 17p11.2-pter in all cases. In contrast, tumors of oligodendrocytic, ependymal, or mixed cellular differentiation did not exhibit loss of alleles at any of the loci examined. These data suggest that the somatic attainment of homozygosity for loci on chromosome 17p is frequently associated with the oncogenesis of central nervous system tumors, particularly those showing solely astrocytic differentiation, and that mitotic recombination mapping is a useful approach towards the subregional localization of a locus whose rearrangement is involved in this disease.

Deletion mapping in human renal cell carcinoma

The highest incidence of renal cell carcinoma (RCC) is reported in Scandinavia. Cytogenetic studies of constitutional tissue in families with hereditary RCC and of sporadic RCC tumor tissue have shown abnormalities of chromosome 3p. In a study of 23 sporadic Scandinavian cases using restriction fragment length polymorphism analysis, we found that 68% of informative patients showed terminal 3p deletions. The break point was not consistent. Loss of a locus on the Y chromosome was seen in 4/14 male patients. Losses of heterozygosity on autosomes included chromosomes 18 (5/15 informative cases) and 17 (3/11 informative cases). Losses in heterozygosity were also found at lower levels for other chromosomes (chromosome 13, 3/16; chromosome 10, 2/19; and chromosome 11, 2/24). The single familial case showed reduplication of part of chromosome 3p and of one chromosome 17. Our data confirm earlier data on losses on chromosome 3p in tumor tissue and by extending this type of analysis to all chromosomes, demonstrate the specificity of this loss. No unique findings were made in the sporadic Scandinavian cases. The results support the thesis that a tumor suppressor gene involved in the oncogenesis of RCC may be located distal to the DNF15S2 locus on chromosome 3p.

Immunohistochemistry of a spontaneous murine ovarian teratoma with neuroepithelial differentiation. Neuron-associated beta-tubulin as a marker for primitive neuroepithelium

Spontaneous ovarian teratomas develop in a large proportion of female LT strain mice. These tumors display a large neuroectodermal component with morphologic differentiation ranging from primitive neuroepithelium (medulloepithelial and ependymoblastic rosettes) to mature neurons, and provide a useful system for the study of various asynchronous stages of neuroepithelial differentiation. The aim of this study was to assess the expression of various cytoskeletal proteins in conjunction with other differentiation-related antigens in these tumors. We found that the medulloepithelial rosettes reacted with only two anti-beta-tubulin monoclonal antibodies. One of these (TU27) recognizes an epitope common to all of the mammalian beta-tubulin isotypes. The other monoclonal antibody (TUJ1) recognizes an epitope unique to class III beta-tubulin isotypes (neuronal-associated). Whereas immunoreactivity in the ependymoblastic rosettes was limited to TU27, differentiating polar neuroblasts reacted with both TU27 and TUJ1 and expressed neuron-specific enolase, synaptophysin, and the 68 kilodalton subunit of neurofilament protein. In well-differentiated foci, mature neurons were positive for all three neurofilament protein subunits (68, 168 and 200 kilodaltons), microtubule-associated-protein 2, synaptophysin, and neuron-specific-enolase, and reacted with both TU27 and TUJ1. By contrast, glial elements expressed glial fibrillary acidic and S-100 proteins, Leu-7 and TU27 but not TUJ1. Myelin basic protein and myelin-associated glycoprotein reactivity was found in the neuropile of these mature areas. The neuroepithelial components were negative for retinal S-antigen and cytokeratin. The expression of the class III beta-tubulin isotype by medulloepithelial rosettes suggests that this isotype may be one of the earliest markers to signal neuronal commitment in primitive neuroepithelium.

Induction of GFAP production in human glioma lines grafted into the anterior chamber of the rat eye

Three established glial fibrillary acidic protein (GFAP)-negative cell lines from human gliomas were transplanted to the anterior chamber of the rat eye. Short-term survival was seen with all transplants. The cells expressed GFAP following transplantation. For comparison, 4 GFAP-positive cell lines were transplanted. With grafting of 5000 cells of any of 6 bipolar cell lines, the transplanted cells could be seen to develop multiple, slender processes reminiscent of mature astrocytes. When 50,000 cells were grafted, vascularized cell mats covering the corneae were seen. The induction of GFAP production and the phenotypic changes were interpreted as signs of differentiation induced by the new environment. All transplanted cells were rejected after 8 weeks.

Potassium and sodium channels in human malignant glioma cells

Human malignant glioma cells from 5 different cell lines were voltage clamped and examined for the presence of depolarization-activated ion channels. Outward K-currents were elicited at membrane potentials greater than 40 mV, which had two main components, one which was delayed and blocked by externally applied tetraethylammonium (TEA, 10 mM), and another which was instantaneous and insensitive to TEA in the outside solution. The proportion of the two K-current components varied between cell lines. An increase in [Ca2+]o in the range 0-4 mM, decreased the leak conductance and shifted the activation of the instantaneous outward K-current towards more positive potentials. Mg2+, Zn2+ and Co2+ had qualitatively similar effects. Patch recordings with 150-160 mM K+-solution on both sides of the membrane revealed that the delayed outward K-current was carried through large conductance (250-300 pS) channels. Changes in free [Ca2+]i from 0 to 2 x 10(-8) M increased the activation of the large conductance K-channel. Small Na-currents were identified in cells from one cell line (Tp-378MG). The Na-conductance ranged from 0.5 to 7.5 nS in 25% of the cells, and was less than 0.5 nS in 75%. The Na-channels were activated and inactivated at 30-40 mV more positive potentials than in the mammalian peripheral nerve. Tetrodotoxin (100 nM) blocked gNa almost completely.

Inward rectifying potassium channels in human malignant glioma cells

Human glioma cells obtained from established cell lines (Tp-276MG, Tp-301MG, Tp-378MG, Tp-483MG and U-251MG) were analyzed for the presence of ion channels with the tight-seal voltage clamp technique. The current-voltage relation revealed a marked inward rectification at hyperpolarizing voltages, due to the presence of inward rectifying K-channels in cells from all studied cell lines. These channels were conducting when the membrane potential was more negative than the K-equilibrium potential. The slope conductance for the inward K-currents (gKi) was affected both by [K+]i and [K+]o. gKi was proportional to [K+]o raised to 0.35 or 0.50, of which the larger value was measured in the presence of low [K+]i (25 mM). The rectification was not significantly different in cells perfused with Mg-free EDTA-buffered internal solution. Tl+ was 3.5 times more permanent than K+. gKi was blocked by Cs+ (1 mM) in a voltage-dependent way (more effective in the hyperpolarized membrane), and by Na+ (154 mM) depending on voltage and time. From measurements of unitary current events in membrane patches (outside out or cell attached) the conductance of the single inward rectifying channel was estimated to be 27 +/- 7 pS. This type of ion channel may be important for K-uptake by glial cells and hence for the K-homeostasis in the brain.

Prolonged survival and vascularization of xenografted human glioblastoma cells in the central nervous system of cyclosporine A treated rats

Glioblastoma cells from three established lines were transplanted in oculo and in cerebrum to rat hosts. A very low dose of Cyclosporine A was found sufficient to allow graft survival whereas grafts in non-immunosuppressed animals did not survive. Moderate immunosuppression permitted long term graft survival without aggressive growth of glioblastoma cells, creating a protracted course during which neither cell rejection nor tumor proliferation occurred. A tumor reminiscent of a glioblastoma was only seen in one animal on high immunosuppression. Phenotypic changes such as the induction of glial fibrillary acidic protein (GFAP) production and an astrocytic morphology were observed in the cells growing in oculo but not in cerebrum. Vascularization was easily demonstrated with laminin immunofluorescence but the endothelial proliferation typical of glioblastomas was not seen.

Transthyretin in endocrine pancreatic tumors

The occurrence of transthyretin (TTR) in 25 endocrine pancreatic tumors was investigated by immunohistochemical methods using both polyclonal and monoclonal antibodies. All malignant insulinomas were strongly TTR immunoreactive, more so than their benign counterparts, which in some cases were TTR negative. All glucagonomas and nonfunctioning tumors were TTR immunoreactive, whereas gastrinomas and VIPomas were TTR negative. TTR, chromogranin A, and the argyrophil reaction (Grimelius' silver technique) had similar distributions among the cells in many, but not all, tumors. Coexistence of TTR with glucagon, insulin, or pancreatic polypeptide in tumor cells was demonstrated. TTR was also quantitated in preoperative serum samples by electroimmuno assay in some cases. Although one patient with a glucagonoma had a markedly increased serum TTR level, five other patients with endocrine tumors, including two patients with glucagonoma, had TTR levels in serum that were within or below the reference range.

Neuroblastic differentiation potential of the human retinoblastoma cell lines Y-79 and WERI-Rb1 maintained in an organ culture system. An immunohistochemical, electron microscopic, and biochemical study

The differentiation potential of the human retinoblastoma cell lines Y-79 and WERI-Rb1 was evaluated in vitro for up to 120 days in a matrix system and in rotary suspension for 30 days. Matrix cultures were grown with 10% fetal calf serum (FCS), with and without differentiation-promoting agents. The latter were applied for a total of 5-45 days (usually 30 days) and included 7S nerve growth factor, dibutyryl cyclic AMP, sodium butyrate, retinoic acid, hydrocortisone, and ascorbic acid. Fully defined, serum-free medium and medium containing 5 or 15% FCS were also used for matrix cultures, and medium with 5 or 10% FCS for suspension cultures. By immunoperoxidase (performed on matrix cultures, both untreated and treated for 30 days with differentiation-promoting agents), the cells of both lines were positive for neuron-specific enolase (NSE), microtubule-associated protein 2 (MAP2), class III beta-tubulin (human h beta 4) isotype, and synaptophysin. In addition, the WERI-Rb1 cells expressed 200 kd neurofilament protein (NFP-H) and retinal S-antigen. Both lines were invariably negative for glial fibrillary acidic (GFA) protein, myelin-associated glycoprotein, myelin basic protein, the epitope recognized by the Leu-7 monoclonal antibody, opsin, and hydroxy-indole-O-methyltransferase. In the Y-79 line the presence of NSE and the absence of NF proteins-H, -M and -L, of GFA protein, and of retinal S-antigen were confirmed biochemically. No differentiated features were found by electron microscopy in either line. Thus, in the matrix system employed, both lines exhibited solely a potential for neuroblastic differentiation, which was more advanced in the WERI-Rb1 line, as reflected by the antigenic expression of NFP-H and of retinal S-antigen.

Transthyretin immunoreactivity in human and porcine liver, choroid plexus, and pancreatic islets

We examined transthyretin immunoreactivity (TTR-IR) in human and porcine liver, choroid plexus, and pancreatic islets with both polyclonal and monoclonal antibodies to TTR. The specificity of the immunoreactions and the effects of various fixatives were tested in immunohistochemical and dot-blot systems. B-5 fixative (mercuric chloride and sodium acetate in formalin) was the best immunopreservative. In both species, the TTR-IR in choroid plexus epithelial cells was strong and was much greater than that in hepatocytes. Glucagon cells in pancreatic islets were also strongly TTR immunoreactive. Insulin cells were slightly TTR immunoreactive in human but strongly so in porcine pancreas. The finding of TTR-IR in normal islets explains the presence of TTR-IR in human endocrine pancreatic tumors, notably glucagonomas and malignant insulinomas.

Clonal genomic alterations in glioma malignancy stages

Comparison of constitutional and tumor genotypes at chromosomal loci defined by restriction fragment length alleles has proven useful in determining the genomic position and tissue specificity of recessive mutations that predispose to cancer (Hansen, M.F., and Cavenee, W.K. Cancer Res., 47:5518-5527, 1987). Here we have applied this approach to 53 unrelated patients with glial tumors of varying histological malignancy grade. Loss of constitutional heterozygosity for loci on chromosome 10 was observed in 28 of 29 tumors histologically classified as glioblastoma (malignancy grade IV) whereas no similar losses were observed in any of 22 gliomas of lower malignancy grade. Examination of restriction fragment length alleles on other chromosomes revealed that loss of sequences on chromosomes 13, 17, or 22 had occurred at nonrandom frequencies and in at least one instance of each malignancy grade of adult glioma. The tumors in which loss of constitutional heterozygosity was observed were composed of one or a mixture of glial cell subtypes displaying astrocytic, oligodendrocytic, and/or ependymal differentiation. These results demonstrate a close association of the loss of chromosome 10 sequences with the most malignant histological stage of glioma and that glioblastoma arises as the clonal expansion of an earlier staged precursor. Furthermore they suggest that glioblastoma is a common phenotypic and malignancy terminus for glial tumors of various cellular subtypes which is reached through a common molecular pathway. This approach which involves the identification of malignancy stage specific somatic losses of heterozygosity provides a genotypic, rather than phenotypic, analysis of tumor progression.

Sialyllactotetraosylceramide, a ganglioside marker for human malignant gliomas

The ganglioside composition of surgically removed human glioma tissue was shown to differ from that of normal adult brain tissue. First, it contained reduced amounts of the major normal brain gangliosides of the gangliotetraose series. Second, it contained increased proportions of gangliosides not detected in normal brain tissue. One of these was isolated and established as being sialyllactotetraosylceramide 3'-isoLM1. Radioimmunoassay for this ganglioside antigen in human glioma tissue revealed that 14/14 specimens of grades III and IV were positive but only 1/4 of grade II. Normal brain tissue was negative. These results suggest that sialyllactotetraosylceramide is a marker for human malignant gliomas.