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  • 1
    Electronic Resource
    Electronic Resource
    Expression of neurofibromatosis 2 protein in human brain tumors: an immunohistochemical study (1997)
    Springer
    Acta neuropathologica 93 (1997), S. 225-232 
    Details
    ISSN: 1432-0533
    Keywords: Key words Neurofibromatosis 2 ; Merlin ; Brain ; tumors ; Immunofluorescence ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The neurofibromatosis 2 (NF2) gene-encoded protein, named merlin, may function as a molecular linkage connecting cytoskeleton and plasma membrane. Merlin is thought to play a crucial role as a tumor suppressor not only in hereditary NF2-related tumors, but also in sporadic tumors such as schwannomas, meningiomas and gliomas. Using a merlin-expression vector system, we raised specific antiserum against merlin. We observed the intracellular distribution of merlin in cultured glioma cells, and further investigated merlin expression in 116 human brain tumors. Immunofluorescence microscopy revealed that merlin was localized beneath the cell membrane and concentrated at cell-to-cell adhesion sites, where actin filaments are densely associated with plasma membrane. By immunohistochemistry, none of the schwannomas from either NF2 patients or sporadic cases showed any immunoreactivity, while normal Schwann cells of cranial nerves were immunopositive. In meningiomas, merlin expression was frequently seen in the meningothelial subtype (8/10, 80%), but no expression could be detected in either the fibrous or the transitional variant. Most normal astrocytes were negative; however, reactive astrocytes often expressed merlin. Glioblastomas and anaplastic astrocytomas were found to be strongly positive, and focal positive staining was observed in fibrillary and pilocytic astrocytomas. Thus, the loss of merlin appears to be integral to schwannoma formation and the differential pathogenesis of meningioma subtypes. However, merlin alterations do not appear to play a critical role in either the tumorigenesis or malignant transformation of neoplastic astrocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004010050608
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  • 2
    Electronic Resource
    Electronic Resource
    α-Synuclein is expressed in a variety of brain tumors showing neuronal differentiation (2000)
    Springer
    Acta neuropathologica 99 (2000), S. 154-160 
    Details
    ISSN: 1432-0533
    Keywords: Key wordsα-Synuclein ; Brain tumors ; Neuronal ¶differentiation ; Immunohistochemistry ; Neuronal marker
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract α-Synuclein is presynaptic nerve terminal protein and its immunoreactivity has been observed in such neurodegenerative structures as senile plaques of Alzheimer’s disease or Lewy bodies of Parkinson’s disease. The physiological role of α-synuclein is still unknown. It is speculated that α-synuclein may be expressed in brain tumors, especially in those showing neuronal differentiation. We examined the immunohistochemical localization of α-synuclein in 77 human brain tumors. α-Synuclein was widely distributed in the brain tumors showing neuronal differentiation. As a result, positive immunostaining for α-synuclein was observed in ganglioglioma, medulloblastoma, neuroblastoma, primitive neuroectodermal tumor, pineocytoma/pineoblastoma, and central neurocytoma. Compared with other neuronal markers, the positive ratio of α-synuclein was not as high as synaptophysin, microtubule-associacted protein 2, neuron-specific enolase and tau, but it was higher than neurofilament and chromogranin A. The expression of synaptophysin was diffusely observed in the cytoplasm, cellular processes and nucleus in tumors showing neuronal differentiation; however, the expression of α-synuclein was predominantly observed in the cytoplasm of the tumors as well as in the cellular processes. On the other hand, non-neuronal brain tumors such as astrocytic tumors or meningiomas were totally negative for α-synuclein. In conclusion, the appearance of an α-synuclein-positive structure was not limited to neurodegenerative diseases, but could also be detected in neoplastic cells showing neuronal differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00007419
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  • 3
    Electronic Resource
    Electronic Resource
    Detection of SV40 T antigen genome in human gliomas (1997)
    Springer
    Brain tumor pathology 14 (1997), S. 125-129 
    Details
    ISSN: 1861-387X
    Keywords: SV40 ; Brain tumor ; PCR ; Southern hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The monkey polyomavirus simian virus 40 (SV40) has been reported to be associated with tumorigenesis of human neoplasms, mainly brain tumors. However, it remains controversial whether the virus really exists in human neoplasms and how the virus transforms human cells in vivo. We investigated the presence of SV40 T antigen genome in 33 human glioma tissue specimens from Japanese patients with different histopathologies by means of the polymerase chain reaction (PCR) followed by Southern blotting. The SV40 T antigen genome was amplified in 4 of the 13 ependymomas (31%) and 3 of the 20 other histotypes of gliomas (15%), whereas in the 22 nontumoral brain tissue specimens, only one case was found to be positive. DNA sequencing confirmed the PCR products to be those of SV40 T antigen. The findings thus suggest that the SV40 genome appears to exist in a certain population of brain tumors from Japanese patients, and that it may also play a role in the oncogenicity or maintenance of the transformed state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02478881
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  • 4
    Electronic Resource
    Electronic Resource
    Accumulation of class I mutant p53 and apoptosis induced by carboplatin in a human glioma cell line (1998)
    Springer
    Brain tumor pathology 15 (1998), S. 77-82 
    Details
    ISSN: 1861-387X
    Keywords: p53 ; Class I mutant ; Apoptosis ; Chemotherapy ; Glioma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Following DNA damage, wild-type p53 increases and mediates the multiple cellular responses for the repair of DNA damage or apoptosis. Inactivation of p53 by single-amino-acid substitutions contributes to the malignant phenotype and confers resistance to therapy. Among tumor-derived p53 mutants, class I mutants still retain a native-like three-dimensional structure, whereas class II mutants have unfolded DNA-binding domains. Sequencing analysis demonstrated that a human glioma cell line (U-373MG) had only a class I mutant form of p53 of His273, which targets an Arg273 that contacts DNA but retains the native structure. In this study, we investigated the metabolic alteration of the class I mutant p53 in apoptosis of U-373MG. The cell cycle progression of U-373MG cells was affected by the addition of carboplatin, while the amount of mutant p53 also increased in their nuclei. The treated cells underwent apoptosis 48h after exposure to 50 μg/ml carboplatin. Although the exact mechanism of the class I mutant p53 in the process of apoptosis has not yet been clarified, the fact that accumulation of the activated mutant p53 in the nucleus of U-373MG is concomitant with apoptosis, just as wild-type p53 does, implies that the class I mutant p53 might retain the ability to participate in apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02478887
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