The Experts below are selected from a list of 192 Experts worldwide ranked by ideXlab platform
George H De Vries - One of the best experts on this subject based on the ideXlab platform.
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Neurofibrosarcoma‐derived Schwann cells overexpress platelet‐derived growth factor (PDGF) receptors and are induced to proliferate by PDGF BB
Journal of Cellular Physiology, 1998Co-Authors: Ali Badache, George H De VriesAbstract:Neurofibromatosis type 1 (NF1) is characterized by the formation of neurofibromas, benign tumors of the peripheral nerve consisting essentially of Schwann cells, which can sometimes turn malignant to form Neurofibrosarcomas. The mechanism of progression toward a malignant phenotype remains largely unknown. In this report, we show that platelet-derived growth factor (PDGF) BB, and to a lesser extent fibroblast growth factor 2, are mitogenic for two Neurofibrosarcoma-derived Schwann cell lines, but not for a Schwann cell line derived from a schwannoma (from a non-NF1 patient) or for transformed rat Schwann cells. Levels of expression of both PDGF receptor α and β are significantly increased in the two Neurofibrosarcoma-derived cell lines compared to the non-NF1 Schwann cell lines. The level of tyrosyl-phosphorylated PDGF receptor β is strongly increased upon stimulation by PDGF BB. In comparison, only modest levels of tyrosyl-phosphorylated PDGF receptor α are observed, upon stimulation by PDGF AA or PDGF BB. Accordingly, PDGF AA is only a weak mitogen for the Neurofibrosarcoma-derived cells by comparison to PDGF BB. These results indicate that the mitogenic effect of PDGF BB for the Neurofibrosarcoma-derived Schwann cell lines is primarily transduced by PDGF receptor β. Neu differentiation factor β, a potent mitogen for normal Schwann cells, was unable to stimulate proliferation of the transformed Schwann cell lines, due to a dramatic down-regulation of the erbB3 receptor. Therefore, aberrant expression of growth factor receptors by Schwann cells, such as the PDGF receptors, could represent an important step in the process leading to Schwann cell hyperplasia in NF1. J. Cell. Physiol. 177:334–342, 1998. © 1998 Wiley-Liss, Inc. The information in the article does not reflect government policy and no official endorsement should be inferred.
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Neurofibrosarcoma derived schwann cells overexpress platelet derived growth factor pdgf receptors and are induced to proliferate by pdgf bb
Journal of Cellular Physiology, 1998Co-Authors: Ali Badache, George H De VriesAbstract:Neurofibromatosis type 1 (NF1) is characterized by the formation of neurofibromas, benign tumors of the peripheral nerve consisting essentially of Schwann cells, which can sometimes turn malignant to form Neurofibrosarcomas. The mechanism of progression toward a malignant phenotype remains largely unknown. In this report, we show that platelet-derived growth factor (PDGF) BB, and to a lesser extent fibroblast growth factor 2, are mitogenic for two Neurofibrosarcoma-derived Schwann cell lines, but not for a Schwann cell line derived from a schwannoma (from a non-NF1 patient) or for transformed rat Schwann cells. Levels of expression of both PDGF receptor α and β are significantly increased in the two Neurofibrosarcoma-derived cell lines compared to the non-NF1 Schwann cell lines. The level of tyrosyl-phosphorylated PDGF receptor β is strongly increased upon stimulation by PDGF BB. In comparison, only modest levels of tyrosyl-phosphorylated PDGF receptor α are observed, upon stimulation by PDGF AA or PDGF BB. Accordingly, PDGF AA is only a weak mitogen for the Neurofibrosarcoma-derived cells by comparison to PDGF BB. These results indicate that the mitogenic effect of PDGF BB for the Neurofibrosarcoma-derived Schwann cell lines is primarily transduced by PDGF receptor β. Neu differentiation factor β, a potent mitogen for normal Schwann cells, was unable to stimulate proliferation of the transformed Schwann cell lines, due to a dramatic down-regulation of the erbB3 receptor. Therefore, aberrant expression of growth factor receptors by Schwann cells, such as the PDGF receptors, could represent an important step in the process leading to Schwann cell hyperplasia in NF1. J. Cell. Physiol. 177:334–342, 1998. © 1998 Wiley-Liss, Inc. The information in the article does not reflect government policy and no official endorsement should be inferred.
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Expression of Kit in neurofibromin-deficient human Schwann cells: role in Schwann cell hyperplasia associated with type 1 neurofibromatosis.
Oncogene, 1998Co-Authors: Ali Badache, Naser Muja, George H De VriesAbstract:Type 1 Neurofibromatosis (NF1) is characterized by the formation of neurofibromas, benign tumors composed mainly of Schwann cells, which can turn malignant to form Neurofibrosarcomas. Neurofibromin, the protein product of the Nf1 gene, is believed to act as a tumor suppressor, accelerating the conversion of the oncogene Ras to its inactive form. The absence of neurofibromin could therefore lead to higher Ras activity in Schwann cells, resulting in uncontrolled growth through a cascade of events not yet elucidated. We describe the abnormal expression of high levels of the Kit tyrosine kinase receptor in both NF1-derived Schwann cell lines and tissue, as compared to primary Schwann cells or schwannoma-derived cells. High levels of Kit expression in the Neurofibrosarcoma-derived Schwann cells correlate with a decrease in neurofibromin expression. Using inhibitors of tyrosine kinase receptors, we found that proliferation of the Neurofibrosarcoma-derived cells is dependent upon activation of a subclass of tyrosine-kinase receptors. The proliferation of these cells is not dependent upon an autocrine loop involving typical Schwann cell mitogens. Finally, the proliferation of the Neurofibrosarcoma-derived Schwann cells can be increased by stimulation with Kit ligand. These data implicate Kit as one of the components leading to the Schwann cell hyperplasia observed in NF1.
Ali Badache - One of the best experts on this subject based on the ideXlab platform.
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Neurofibrosarcoma‐derived Schwann cells overexpress platelet‐derived growth factor (PDGF) receptors and are induced to proliferate by PDGF BB
Journal of Cellular Physiology, 1998Co-Authors: Ali Badache, George H De VriesAbstract:Neurofibromatosis type 1 (NF1) is characterized by the formation of neurofibromas, benign tumors of the peripheral nerve consisting essentially of Schwann cells, which can sometimes turn malignant to form Neurofibrosarcomas. The mechanism of progression toward a malignant phenotype remains largely unknown. In this report, we show that platelet-derived growth factor (PDGF) BB, and to a lesser extent fibroblast growth factor 2, are mitogenic for two Neurofibrosarcoma-derived Schwann cell lines, but not for a Schwann cell line derived from a schwannoma (from a non-NF1 patient) or for transformed rat Schwann cells. Levels of expression of both PDGF receptor α and β are significantly increased in the two Neurofibrosarcoma-derived cell lines compared to the non-NF1 Schwann cell lines. The level of tyrosyl-phosphorylated PDGF receptor β is strongly increased upon stimulation by PDGF BB. In comparison, only modest levels of tyrosyl-phosphorylated PDGF receptor α are observed, upon stimulation by PDGF AA or PDGF BB. Accordingly, PDGF AA is only a weak mitogen for the Neurofibrosarcoma-derived cells by comparison to PDGF BB. These results indicate that the mitogenic effect of PDGF BB for the Neurofibrosarcoma-derived Schwann cell lines is primarily transduced by PDGF receptor β. Neu differentiation factor β, a potent mitogen for normal Schwann cells, was unable to stimulate proliferation of the transformed Schwann cell lines, due to a dramatic down-regulation of the erbB3 receptor. Therefore, aberrant expression of growth factor receptors by Schwann cells, such as the PDGF receptors, could represent an important step in the process leading to Schwann cell hyperplasia in NF1. J. Cell. Physiol. 177:334–342, 1998. © 1998 Wiley-Liss, Inc. The information in the article does not reflect government policy and no official endorsement should be inferred.
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Neurofibrosarcoma derived schwann cells overexpress platelet derived growth factor pdgf receptors and are induced to proliferate by pdgf bb
Journal of Cellular Physiology, 1998Co-Authors: Ali Badache, George H De VriesAbstract:Neurofibromatosis type 1 (NF1) is characterized by the formation of neurofibromas, benign tumors of the peripheral nerve consisting essentially of Schwann cells, which can sometimes turn malignant to form Neurofibrosarcomas. The mechanism of progression toward a malignant phenotype remains largely unknown. In this report, we show that platelet-derived growth factor (PDGF) BB, and to a lesser extent fibroblast growth factor 2, are mitogenic for two Neurofibrosarcoma-derived Schwann cell lines, but not for a Schwann cell line derived from a schwannoma (from a non-NF1 patient) or for transformed rat Schwann cells. Levels of expression of both PDGF receptor α and β are significantly increased in the two Neurofibrosarcoma-derived cell lines compared to the non-NF1 Schwann cell lines. The level of tyrosyl-phosphorylated PDGF receptor β is strongly increased upon stimulation by PDGF BB. In comparison, only modest levels of tyrosyl-phosphorylated PDGF receptor α are observed, upon stimulation by PDGF AA or PDGF BB. Accordingly, PDGF AA is only a weak mitogen for the Neurofibrosarcoma-derived cells by comparison to PDGF BB. These results indicate that the mitogenic effect of PDGF BB for the Neurofibrosarcoma-derived Schwann cell lines is primarily transduced by PDGF receptor β. Neu differentiation factor β, a potent mitogen for normal Schwann cells, was unable to stimulate proliferation of the transformed Schwann cell lines, due to a dramatic down-regulation of the erbB3 receptor. Therefore, aberrant expression of growth factor receptors by Schwann cells, such as the PDGF receptors, could represent an important step in the process leading to Schwann cell hyperplasia in NF1. J. Cell. Physiol. 177:334–342, 1998. © 1998 Wiley-Liss, Inc. The information in the article does not reflect government policy and no official endorsement should be inferred.
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Expression of Kit in neurofibromin-deficient human Schwann cells: role in Schwann cell hyperplasia associated with type 1 neurofibromatosis.
Oncogene, 1998Co-Authors: Ali Badache, Naser Muja, George H De VriesAbstract:Type 1 Neurofibromatosis (NF1) is characterized by the formation of neurofibromas, benign tumors composed mainly of Schwann cells, which can turn malignant to form Neurofibrosarcomas. Neurofibromin, the protein product of the Nf1 gene, is believed to act as a tumor suppressor, accelerating the conversion of the oncogene Ras to its inactive form. The absence of neurofibromin could therefore lead to higher Ras activity in Schwann cells, resulting in uncontrolled growth through a cascade of events not yet elucidated. We describe the abnormal expression of high levels of the Kit tyrosine kinase receptor in both NF1-derived Schwann cell lines and tissue, as compared to primary Schwann cells or schwannoma-derived cells. High levels of Kit expression in the Neurofibrosarcoma-derived Schwann cells correlate with a decrease in neurofibromin expression. Using inhibitors of tyrosine kinase receptors, we found that proliferation of the Neurofibrosarcoma-derived cells is dependent upon activation of a subclass of tyrosine-kinase receptors. The proliferation of these cells is not dependent upon an autocrine loop involving typical Schwann cell mitogens. Finally, the proliferation of the Neurofibrosarcoma-derived Schwann cells can be increased by stimulation with Kit ligand. These data implicate Kit as one of the components leading to the Schwann cell hyperplasia observed in NF1.
Surya Rednam - One of the best experts on this subject based on the ideXlab platform.
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hemisacrectomy with preservation of the contralateral sacral nerve roots and sacroiliac joint for pelvic Neurofibrosarcoma in a 7 year old child case report with 2 year follow up
Journal of Neurosurgery, 2017Co-Authors: Ali H Palejwala, Jared Fridley, Krystal Garcia, Sanjeev A Vasudevan, David Y Khechoyan, Surya RednamAbstract:Neurofibrosarcoma is rare in the pediatric age group. A malignant tumor of the sacrum presents significant challenges, especially if the goals are to resect with wide and clean surgical margins and to achieve acceptable functional outcomes. The authors report a case of this rare tumor affecting the sacrum and sacral nerve roots of a 7-year-old girl and review the role of total hemisacrectomy sparing the contralateral sacral nerve roots and lumbopelvic reconstruction in the treatment of this disease. This patient is, to the best of the authors' knowledge, the youngest to be treated in this manner.
C J Obrien - One of the best experts on this subject based on the ideXlab platform.
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malignant spinal Neurofibrosarcoma
Spine, 2000Co-Authors: R Kettwhite, J L Martin, E W Jones, C J ObrienAbstract:STUDY DESIGN: A report of a case of metastatic spinal Neurofibrosarcoma. OBJECTIVE: To document metastatic Neurofibrosarcoma as a cause of spinal cord compression and to review the literature. SUMMARY OF BACKGROUND DATA: Three previously reported cases of metastatic Neurofibrosarcoma of the spine were reviewed. METHODS: The patient's clinical record and radiologic investigations as well as the result of a search of the English literature are reported. Magnetic resonance images, computed tomographic scans, and histology photomicrographs are displayed. RESULTS: Paraparesis developed in this patient, due to a posterior extradural thoracic spinal cord compression by a Neurofibrosarcoma believed to be metastatic from a Neurofibrosarcoma of the femoral nerve. CONCLUSIONS: Malignant spinal metastasis remains a rare complication of neurofibromatosis, with a very poor prognosis.
Teri A Longacre - One of the best experts on this subject based on the ideXlab platform.
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endocervical fibroblastic malignant peripheral nerve sheath tumor Neurofibrosarcoma report of a novel entity possibly related to endocervical cd34 fibrocytes
The American Journal of Surgical Pathology, 2011Co-Authors: Anne M Mills, Jason Karamchandani, Hannes Vogel, Teri A LongacreAbstract:: Primary cervical stromal sarcomas are rare neoplasms that have been poorly characterized. We report the clinical, histologic, and immunohistologic features of 3 primary endocervical S100 protein (S100p)-positive and CD34-positive sarcomas, herein designated as fibroblastic malignant peripheral nerve sheath sarcoma (endocervical Neurofibrosarcoma), 2 of which occurred in women younger than 35 years of age. All tumors presented as a cervical polyp or mass lesion; 1 extended into the pelvic side wall and vaginal soft tissue. The tumors measured 2.0 to 8.0 cm, and were composed of compact fascicles of spindled cells arranged in herringbone, loose fascicular, or ill-defined storiform patterns. A focal whorled architecture was identified in all 3 tumors, but distinct Antoni A areas and Verocay bodies were absent. Ultrastructural examination in 1 case confirmed the presence of fibrocyte-like differentiation. Strong, diffuse, and in 1 case, patchy S100p expression was seen in all cases; strong and diffuse CD34 expression was also present in all tumors. Adjacent uninvolved endocervical stroma also showed CD34 positivity but expression was much less dramatic than in tumor cells. All other markers of neural, melanocytic, smooth muscle, endometrial stromal, and epithelial differentiation were negative. One of the tumors behaved extremely aggressively with extensive pelvic involvement, resulting in patient death within 16 months of diagnosis; another tumor was associated with pelvic recurrence 13 months after diagnosis; and the third tumor had an indolent course with no evidence of recurrence at 33 months after complete excision and local radiotherapy, although follow-up was limited. Review of large numbers of mesenchymal tumors in the uterus did not show similar tumors. Endocervical Neurofibrosarcoma should be distinguished from solitary fibrous tumor, endometrial stromal sarcoma, leiomyosarcoma, melanoma, and other spindle cell neoplasms. The prominent fibroblastic endoneurial-like differentiation seen in this peripheral nerve sheath tumor may be related to the presence of a rich mucosal stromal fibrocyte network in the endocervix.