Navegando por Palavras-chave "astrocytoma"
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- ItemSomente MetadadadosAnálise da expressão do gene kiaa1549-braf e das mutações dos genes idh1 e idh2 em amostras de astrocitomas de baixo grau da infância(Universidade Federal de São Paulo (UNIFESP), 2013-06-26) Cruz, Gabriela Rampazzo [UNIFESP]; Toledo, Silvia Regina Caminada de Toledo [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Low-grade astrocytomas comprise about 30% of the central nervous system tumors in children. Several investigations have looked for the correlation between the KIAA1549-BRAF gene fusions and mutations at IDH1 and IDH2 genes in low grade pediatric astrocytomas. This study analyzed the expression of the fusion gene KIAA1549-BRAF and mutations at exon 4 of the IDH1 and IDH2 genes in samples of PA and A-II pediatric patients. The correlation between these alterations and the clinical profile of the patients were also evaluated. Eighty-four samples of low grade astrocytomas (63 pylocitic astrocytomas – PA – and 21 grade II astrocytomas – A-II) were analyzed by PCR for each of the targets and sequenced to identify specific mutations in the IDH genes. In 47% of the samples we identified the KIAA1549-BRAF fusion transcript. Mutations in the R132/R172 residues of the IDH1/IDH2 genes were detected in only two samples and the G105G polymorphism (rs11554137:C>T) was identified in 10 patients. Additionally, we observed two mutations out of the usual hotspots at IDH1 and IDH2 genes. The survival analysis of the patients considered as clinically relevant demonstrated that those with the KIAA1549-BRAF fusions had a 5-year overall survival of 90% compared with 30% for those who did not have the fusion transcript. We observed a smaller frequency of mutations in IDHs genes than previously described, but since these studies are composed of adult or mixed (adults and children) samples, we believe that our results represent a relevant contribution to the growing knowledge in low grade childhood astrocytomas.
- ItemSomente MetadadadosExpression of HOXC9 and E2F2 are up-regulated in CD133+cells isolated from human astrocytomas and associate with transformation of human astrocytes(Elsevier B.V., 2007-07-01) Okamoto, Oswaldo K.; Oba-Shinjo, Sueli M.; Lopes, Luciana; Marie, Suely K. Nagahashi; Universidade Federal de São Paulo (UNIFESP); Inst Israelita Ensino & Pesquisa Albert EinsteinComparative analysis of cancer stem cells with their neoplastic and non-neoplastic counterparts should help better understand the underlying molecular events leading to transformation and tumor dissemination. Here, we report a molecular signature comprised by genes with exclusive aberrant expression in CD133+ cells, a reported subpopulation of tumorigenic stem-like cells, isolated from human glioblastomas. Microarrays covering 55,000 transcripts were used to compare gene expression profiles in purified subpopulations of CD133+ and CD133- GBM cells. Sixteen genes, many of which not previously associated with astrocytomas, were found aberrantly expressed in CD133+ cells, but not in CD133-, when compared with corresponding non-neoplastic controls. Up-regulation of two of such genes, E2F2 and HOXC9, was detected in a set of 54 astrocytomas of different grades and significantly associated with malignancy. Due to their distinctive expression in CD133+ cells, the use of E2F2 and HOXC9 as therapeutic targets for tumor eradication is suggested. (c) 2007 Elsevier B.V. All rights reserved.
- ItemAcesso aberto (Open Access)Índice de astrócitos gemistocíticos e imuno-expressão da proteína p53 em astrocitomas, grau II e III OMS(Academia Brasileira de Neurologia - ABNEURO, 2001-12-01) Martins, Dely Cristina [UNIFESP]; Stávale, João Norberto [UNIFESP]; Malheiros, Suzana Maria Fleury [UNIFESP]; Santiago, Lucila Heloisa Simardi [UNIFESP]; Roman, Leonor Cristina Manoja [UNIFESP]; Aguiar, Kátia Cilene Carozzi [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Twenty-two patients with astrocytomas, grade II or III WHO, were studied from 1990 to 1998. In all cases, histopathology showed that the astrocytomas had a gemistocytic component. The aims of this study were to establish the fraction of gemistocytic astrocytes, to investigate p53 protein immunoexpression and to evaluate correlations between these two parameters with the tumour outcome. Tumor cells were quantified at high-power magnification (x400). At least 1000 neoplastic cells (small neoplastic astrocytes plus gemistocytes) were counted in each specimen. The percentage of gemistocytes was defined as the gemistocytic index. Nuclear expression of p53 protein was evaluated in neoplastic astrocytes and gemistocytes. Both the frequency (7/22) as well the p53 immunoexpression indices in gemistocytes, regardless of the grade of the astrocytomas, were inferior from those reported in the literature. No correlation was found between the gemistocytic indices and the p53 immunoexpression.
- ItemAcesso aberto (Open Access)Malignant transformation of pleomorphic xanthoastrocytoma: case report(Academia Brasileira de Neurologia - ABNEURO, 2003-03-01) Tella Junior, Oswaldo Ignácio de [UNIFESP]; Herculano, Marco Antonio; Prandini, Mirto Nelso [UNIFESP]; Stávale, João Norberto [UNIFESP]; Aguiar, Paulo Henrique; Universidade Federal de São Paulo (UNIFESP); Jundiai Medicine School Neurosurgical Department; State University of São Paulo Neurosurgical DepartmentWe report a case of a pleomorphic xantoastrocytoma which manifested itself as a cystic isodense lesion in the right fronto-temporal lobe in a 26 year-old woman. It appeared as a soft yellow tumor with cystic cavities on surgery. Five months after this surgery, the patient was submitted to a new operation, which revealed a friable tumor, easily differentiated from the normal parenchyma, with cystic components. The histopathological examination demonstrated pleomorphic xanthoastrocytoma with malignant transformation. Histologically, the tumor at first procedure was composed of pleomorphic astrocytes with multinucleated and foamy cells. A rare case of malignant transformation in pleomorphic xanthoastrocytoma is presented, discussed and illustrated in this paper.