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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Loss of constitutional heterozygosity is a common molecular feature of cancers in which inactivation of one or more tumor suppressor genes is thought to contribute to tumorigenesis. Recent evidence suggests that the gene responsible for neurofibromatosis, type 1 (NF-1), belongs to this class of heritable cancer genes. Children with NF-1 show an increased incidence of myeloid leukemia, including juvenile chronic myelogenous leukemia (JCML) and, perhaps, the myeloproliferative syndrome (MPS) associated with bone marrow monosomy 7 (Mo 7). We have investigated five children with Mo 7: three with NF-1 and two others with suggestive evidence of NF-1. Southern blotting experiments performed in four patients showed no loss of heterozygosity in bone marrow specimens using probes linked to the NF-1 locus on the long arm of chromosome 17. Both of our patients with familial NF-1 inherited the disease from their mothers, as did 14 of 19 other cases of myeloid leukemia in children with familial NF-1. Seventeen of these 21 children were boys. Myeloid leukemia developed in 12 boys and four girls who inherited NF-1 from their mothers, and in five boys who inherited the disease from their fathers. Father-to-daughter transmission was not observed. Taken together, the presence of chromosome 7 deletions in the leukemias of children with NF-1, a pattern of inheritance favoring maternal transmission of NF-1, and the marked predilection for boys to develop JCML and Mo 7 suggest a multistep mechanism of oncogenesis in which epigenetic factors might play a role. Further investigation is required to determine if the NF-1 genes in the leukemic bone marrows of these patients have acquired point mutations or small deletions.
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PMID:Monosomy 7 myeloproliferative disease in children with neurofibromatosis, type 1: epidemiology and molecular analysis. 153 55

A man with known systemic neurofibromatosis developed an acute upper gastrointestinal hemorrhage while hospitalized after a neurosurgical procedure. Endoscopic evaluation showed a vascular lesion with an appearance consistent with a Dieulafoy-type lesion in the distal esophagus. Despite multiple endoscopic procedures with attempted coagulation of the bleeding lesion, the patient continued to have life-threatening hemorrhaging. At thoractomy, a tumor was found to arise from the vagus nerve at the site of bleeding. This tumor was resected and histologically determined to be a neurilemoma. Acute bleeding into the esophagus associated with this type of tumor has not been previously reported.
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PMID:Acute esophageal hemorrhage from a vagal neurilemoma. 153 96

We experienced an operation of a 16-year-old female of mediastinal vagal neurinoma. Abnormal shadow was pointed out on chest X-ray at physical examination of high school. Right thoracotomy was performed under the diagnosis of mediastinal tumor. There was a walnut sized mass on the right vagal nerve at just peripheral side of the recurrent nerve branch. The vagal nerve was cut at both sides of the mass not to injure the recurrent nerve. The tumor was removed en block. Two little finger sized masses were recognized in serratus anterior muscle and 5 th. intercostal nerve. These removed masses were diagnosed as neurinoma pathologically. While the mother of this case had been admitted on another hospital because of multiple neurinomatosis with bilateral acoustic neurinoma. Thus this case is of familial neurinomatosis, suggesting it's heredity like as neurofibromatosis (von Recklinghausen's disease).
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PMID:[A case of mediastinal vagal nerve neurinoma: a familial neurinomatosis]. 154 97

We report a case of clitoral and renovascular involvement of neurofibromatosis resulting in an enlarged phallus with juvenile hypertension. The patient was successfully treated by removal of the clitoral tumor and nephrectomy. This is the first of 15 reported cases with clitoral involvement, that showed concurrent renovascular hypertension.
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PMID:A case of neurofibromatosis associated with clitoral enlargement and hypertension. 155 29

The neurofibromatosis 1 (NF1) gene product, neurofibromin, contains a GTPase-activating protein (GAP)-related domain, or NF1 GRD, that is able to down-regulate p21ras by stimulating its intrinsic GTPase. Since p21ras.GTP is a major regulator of growth and differentiation, mutant neurofibromins resulting from somatic mutations in the NF1 gene might interfere with ras signaling pathways and contribute to the development of tumors. We describe an amino acid substitution in the NF1 GRD, altering Lys-1423, that has occurred in three tumor types: colon adenocarcinoma, myelodysplastic syndrome, and anaplastic astrocytoma, and in one family with neurofibromatosis 1. The GAP activity of the mutant NF1 GRD is 200- to 400-fold lower than that of wild type, whereas binding affinity is unaffected. Thus, germline mutations in NF1 that cause neurofibromatosis 1 can also occur in somatic cells and contribute to the development of sporadic tumors, including tumors not associated with neurofibromatosis 1.
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PMID:Somatic mutations in the neurofibromatosis 1 gene in human tumors. 156 47

In the past year we have witnessed significant progress in understanding the molecular basis of cancerogenesis and in identifying the genetic determinants of susceptibility to cancer. In particular, the finding that the same tumor suppressor genes play a pathogenic role in both the inherited and the sporadic forms of some childhood tumors has suggested that this gene class may also be involved in adult tumors derived from inherited familial cancer syndromes. The identification of the gene defect underlying the Li-Fraumeni syndrome, a germline mutation of the tumor suppressor gene p53, has fully confirmed that suggestion. Three other genes associated with the inherited cancer syndromes neurofibromatosis type I (NF-1) and familial adenomatous polyposis have been cloned and partially characterized. In addition to these genes, which have a relatively high penetrance and contribute directly to tumorigenesis, other genes that lead to cancer as a secondary effect seem to act in determining an individual's overall cancer risk. The latter genes are most likely related to defective processes of DNA repair or to regulation of carcinogen metabolism. In this context the analysis of models of murine strains with different genetic susceptibility to cancer of various organs may be a useful tool for unveiling the genetic basis for cancer susceptibility in individuals.
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PMID:Genetics and cancer. 159 Dec 84

Neurofibromatosis of the genitourinary system is rare. We present the CT and MR findings of neurofibromas of the bladder in three patients with von Recklinghausen disease (neurofibromatosis, Type 1). In one case, genitourinary involvement was the primary presentation of the disease. Both CT and MR imaging revealed diffuse and nodular bladder wall involvement, along with pelvic sidewall and adjacent soft tissue abnormalities. The CT attenuation coefficients measured near soft tissue density. On T1-weighted spin echo MR images the tumors revealed signal intensity slightly greater than that of skeletal muscle. Neurofibromas showed markedly increased signal intensity on T2-weighted images relative to the surrounding soft tissues, with marked enhancement in two cases imaged following Gd-DTPA administration. Obstructive hydronephrosis was present in all cases, presumably due to neurofibromas involving the trigonal region. Pelvic sidewall tumors were visualized as rounded, nodular masses extending into the obturator foramina. In the evaluation of patients with von Recklinghausen disease, MR imaging, compared with CT, more clearly defined tumor extent within the bladder, pelvic sidewalls, and surrounding soft tissues.
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PMID:CT and MR of neurofibromatosis of the bladder. 159 28

The authors describe the case of a 32 year-old woman with a congenital neurofibromatosis referred for excision of a painful subcutaneous nodule of the left popliteal space. The histological study showed a tumor displaying a biphasic pattern made of fascicles of benign spindle cells admixed with mucinous epithelium. Immunohistochemistry (cytokeratin X, ECA X) and electron microscopy helped to prove the true epithelial nature of the glandular components. Glandular schwannoma has rarely been described, especially in a benign histological pattern; this one has never been reported in association with Von Recklinghausen's disease. The histogenesis of the glandular schwannoma remains uncertain.
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PMID:[Benign glandular schwannoma and Recklinghausen disease. Report of a case]. 159 70

We report on an isolated cervical vagus nerve neurofibroma in a patient with neurofibromatosis Recklinghausen. B-scanechography showed a well limited tumor without infiltration of adjacent structures and with cranial and caudal dendrites. The inner structure of the neurofibroma was characterized by a homogenous picture of low ultrasound reflection. Although ultrasound allows an exact description of the tumor's topography, it is impossible to give a histological interpretation by the sonomorphology.
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PMID:[Ultrasound diagnosis of isolated vagus neurofibroma in Recklinghausen disease]. 160 Mar 66

The expression of the human T-cell lymphotropic virus type 1 (HTLV-1) tax gene in transgenic mice has been shown to result in the development of neurofibromas. Further characterization of these transgenic mice has revealed other significant pathologic similarities between this transgenic mouse model and human neurofibromatosis (NF). Pheochromocytomas of the adrenal medulla and hamartomas of the iris are well-recognized manifestations of human NF. Adrenal medullary tumors have been found in 68% of transgenic animals that were studied. They appear, however, not to be pheochromocytomas, but rather composed of undifferentiated spindle cells. Proliferation of fibroblastlike cells in the iris also occurs in one-half of the transgenic animals surviving more than 6 months. Melanocytes, however, have not been found in the transgenic iris lesion, although they are characteristically found in the Lisch nodules of human NF. The similarities between human neurofibromatosis and this transgenic mouse model (in which the overexpression of a single gene results in neoplasia) are discussed. This transgenic system may provide further insights into molecular mechanisms involved in the pathogenesis of neurofibromatosis.
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PMID:Adrenal medullary tumors and iris proliferation in a transgenic mouse model of neurofibromatosis. 160 7


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