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At least 883 records · Page 49Linked to original sources
PubMed2001

Aberrant hypermethylation of the major breakpoint cluster region in 17p11.2 in medulloblastomas but not supratentorial PNETs.

Deletions of 17p have been consistently reported in up to 50% of medulloblastomas (MBs), and the major breakpoint interval has been localized to chromosome segment 17p11.2. Based on several reports linking aberrant DNA methylation and chromosomal disruption, we examined the methylation pattern in this region by employing restriction landmark genomic scanning (RLGS). Several CpG islands located in the major breakpoint cluster region were identified using a bacterial artificial chromosome (BAC) contig of the breakpoint region. A long-range methylation map was established for 20 MBs and 5 supratentorial primitive neuroectodermal tumors (stPNETs). Selected CpG islands were examined using Southern and bisulfite sequencing analysis. Aberrantly hypermethylated CpG islands in 17p11. 2 were found in 33% of MBs. Interestingly, one CpG island was methylated in MBs, but not in any of the examined stPNETs. A BAC clone covering three of the methylated CpG islands was partially sequenced in the search for a potential tumor suppressor gene. None of the expressed sequence tag sequences and full-length mouse/human cDNAs that were associated with aberrant methylation showed a change in expression levels due to methylation. The potential link between chromosomal instability in 17p11.2 and hypermethylation in this region is discussed.

Adolescent↗
PubMedDate not supplied

Establishment and characterization of malignant rhabdoid tumor of the kidney.

Malignant rhabdoid tumor of the kidney (MRTK) is a highly aggressive tumor which occurs in childhood and which is histologically characterized by the existence of eosinophilic intracytoplasmic inclusions. We established and characterized a cell line from this tumor with histological, immunohistochemical and cytogenetical analysis. Histologically, the tumor cells demonstrate typical eosinophilic inclusions, while immunohistochemically the cells demonstrate common mesenchymal and epithelial differentiation. Although the conventional karyotyping of this tumor lacked the abnormalities of 22q chromosome, Southern blot analysis and microsatellite analysis verified abnormalities of the BCR gene and of the hSNF5/INI1 gene. Despite the variety of locations, these common genetic abnormalities appear to contribute to distinguish rhabdoid tumor from such other small round cell tumors as primitive neuroectodermal tumor, rhabdomyosarcoma, poorly differentiated synovial sarcoma and desmoplastic small round cell tumor.

Animals↗
PubMedDate not supplied

Signal transduction pathway to low-dose radiation-induced apoptosis in peripheral PNET cells.

We investigated the signal transduction pathway to low-dose radiation-induced apoptosis in vitro in the human peripheral primitive neuroectodermal tumor (pPNET) cell line with wild-type p53 established in our laboratory. Apoptosis was induced by 2Gy irradiation in an almost p53-dependent manner in this model except for a deficiency of the cleavage of caspase-9. It was detected 3 hours after irradiation by fragmentation assay. The expressions of p53, p21WAF-1 and Bax increased, in contrast to the gradually decreasing expression of Bcl-2, as observed by immunoblotting. Following this, cleavages of caspase-3 and PARP reached peak levels. There were no detectable increases in ERK expression and caspase-9 cleavage. In respect of the probability of other pathways to apoptosis, this cell line will provide a useful model both for investigating low-dose radiation-induced signal transduction pathway and for analyzing the biological characteristics of pPNET.

Adult↗
PubMedDate not supplied

Fine needle aspiration of peripheral neuroepithelioma of soft tissues.

Peripheral neuroepithelioma of soft tissue is a malignant primitive neuroectodermal tumor that appears both in children and adults and usually has a poor outcome. Fine needle aspiration on two patients with tumors in the lower limbs showed small round cells with unipolar processes and a tendency to form Homer-Wright rosettes. The cells had a round to oval nucleus with fine chromatin, up to four small, conspicuous nucleoli and vacuolated, periodic acid-Schiff-positive cytoplasm. The diagnosis was supported by electron microscopic study of the aspirate, which showed features of neuroblastic differentiation (i.e., neurosecretory granules), and by histologic, immunohistochemical and cytogenetic study of the resected tumors.

Adolescent↗
PubMed1985

Chromosome 1 abnormalities: a common feature of pediatric solid tumors.

Abnormalities of chromosome 1 were found in 32 of 46 pediatric solid tumors including Ewing's sarcoma, Wilms' tumor, rhabdomyosarcoma, primitive neuroectodermal tumor, and hepatoblastoma. Trisomy of 1q was the most common abnormality, and breakpoints were most frequent in the region 1cen to 1p22. Abnormalities of chromosome 1 are not specific to any type of tumor. However, their frequent occurrence indicates that they may endow a clonal advantage in the development of cancer.

Aneuploidy↗
PubMed1986

Computed tomographic characteristics of primary brain tumors in 50 dogs.

Fifty histologically identified primary brain tumors in the dog were analyzed by computed tomography to establish criteria for identifying tumor types by computed tomography characteristics. Meningiomas could be distinguished from tumors within the brain parenchyma because they usually were broad-based, peripherally located masses that were enhanced homogeneously with contrast material. Among parenchymal tumors, astrocytomas were not distinguished easily from oligodendrogliomas because both tumors had similar features of ring-like and nonuniform enhancement, and poorly defined tumor margins. Choroid plexus tumors were seen as well-defined, hyperdense masses that had marked, uniform contrast enhancement. Pituitary tumors were distinguished readily by their location, minimal peritumoral edema, uniform contrast enhancement, and well-defined margins. Distinguishing features of other less frequently seen tumors (ependymoma, primitive neuroectodermal tumor, glioma, and neoplastic reticulosis) were not identified.

Animals↗
PubMedDate not supplied

Cerebral ventricular fluid distribution of subcutaneous granulocyte-macrophage colony stimulating factor.

After treating a child suffering from disseminated primitive neuroectodermal tumor and hydrocephalus with bilateral ventriculostomies, we administered intravenous high dose thiotepa followed by a single subcutaneous dose of GM-CSF 24 hours later. The appearance and clearance of GM-CSF were measured from both ventricles, one of which was surrounded by tumor. Peak levels of GM-CSF were recorded simultaneously in both ventricles 11 hours after injection. Complete clearance from injection required 15 hours and 31 hours for the tumor-free right ventricle and the tumor-involved left ventricular wall, respectively. Tumor response was ephemeral and limited to ventricular fluid WBC, protein and LDH decreases. Microglia were detected; however, there was no evidence of anti-tumor activity in biopsied tumor tissue. Tumored regions of the brain may have perturbation of GM-CSF distribution and clearance which may contribute to the lack of microglial activity.

Brain Neoplasms↗
PubMed1993

[Study on the mechanisms of thrombin to inhibit neurite outgrowth].

In the present study, we investigated the effects and signal transduction mechanisms of thrombin on neuronal differentiation of human primitive neuroectodermal tumor cell line CHP-100. Thrombin inhibited neurite outgrowth of CHP-100 cells in culture induced by serum removal. The inhibitory effects were found to be associated with activation of phosphatidylinositol turnover/calcium mobilization signal transduction pathway by thrombin, since stimulation with thrombin induced significant inositol-1, 4, 5 trisphosphate accumulation and intracellular free calcium transient in CHP-100 cells. In addition, the most potent inhibitor of thrombin hirudin, which reversed the inhibitory effect of thrombin on neurite outgrowth of CHP-100 cells, also inhibited thrombin-stimulated calcium transient. These results suggest a specific role of thrombin signal transduction pathway in the regulation of neuronal differentiation.

Brain Neoplasms↗
PubMed1998

[Teratoid/rhabdoid tumor of the central nervous system].

Teratoid/rhabdoid tumor is a recently introduced infantile brain neoplasm of uncertain origin clinically characterized by a most aggressive course. We describe the case of a 2-year-old boy and a 7-year-old girl, the former presenting with central fever and hemiparesis, while vomiting and headache were symptoms in the latter. A brain tumor in the right fronto-parieto-occipital and the left fronto-medial parenchyma, respectively, were found and removed by surgery. On histology, both lesions consisted of sheets of ovoid cells with prominent cytoplasm, vesicular nuclei and macronucleoli. In the second case, a spindle-cell component and bone metaplasia were also noted. Ultrastructurally, tumor cells contained whorls of intermediate filaments. Immunohistochemistry revealed a polyphenotypic expression profile including positivity for epithelial membrane antigen, vimentin and a-actin. There was no evidence of a germ-cell origin. Chromosomal translocation involving 22q11 was established cytogenetically in the first case. The teratoid/rhabdoid tumor shares many common traits with renal rhabdoid tumors and primitive neuroectodermal tumors as well as germ cell neoplasms; therefore its being an entity is debated.

Brain Neoplasms↗
PubMed1998

[Meningoradiculitis revealing an occult medulloblastoma-PNET in an adult].

Neoplastic meningitis as the presentation of occult primitive neuroectodermal tumor (PNET) is occasionally described in children. We report the case of an 64 year old-man who presented a meningo-radiculopathy with progressive injury of the cauda equina and then the ocular motor nerves, revealing an occult medulloblastoma-PNET.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

Differential responsiveness among "high risk" pediatric brain tumors in a pilot study of dose-intensive induction chemotherapy.

BACKGROUND: These factors have been predictive for progressive disease on therapy (PDOT) among pediatric brain tumors: >1.5 cm(2) unresectable tumor, glioblastoma, supratentorial primitive neuroectodermal tumor, and metastatic medulloblastoma (MBL). This pilot study sought to correlate cytoreductive response with progression free survival. PROCEDURES: Four courses of cisplatinum, cyclophosphamide, etoposide, and vincristine preceded hyperfractionated radiotherapy (RT). Maintenance chemotherapy consisted of eight cycles of carboplatin, etoposide, and vincristine. Biopsy specimens were immunohistochemically studied for labeling index, hypoxia, and multidrug resistance proteins. RESULTS: Twenty newly diagnosed patients [nine primitive neuroectodermal tumors/MBL, one choroid plexus carcinoma, eight malignant gliomas, and two anaplastic ependymomas] were treated. Ten patients, who required neuraxis irradiation, constituted the "PNET" group. These demonstrated five complete and one partial response (PR), with an estimated median progression free survival of 44 months and median survival in excess of 53 months. Patients treated with involved field irradiation were designated the "Glioma" group. Induction chemotherapy produced partial and minor responses (MRs) among 5/10. Their estimated median progression free survival was 6.9 months (P = 0.035 relative to the PNET) with a median survival of 10.7 months (P = 0.04). Age, labeling index, the presence of hypoxia, and Pgp/MDR1 expression failed to discriminate between the two groups. CONCLUSIONS: This induction regimen produced a cytoreductive response in 6/10 and achieved a significant improvement in progression free survival among 7/10 in the PNET group. Unfortunately, responses among Glioma patients did not translate into durable control. Expression of the biologic factors was similar between both groups and did not correlate with diagnosis or response.

Adolescent↗
PubMed2005

[Primary hepatic localization of the PPNET (primitive peripheral neuroectodermal tumors). Case report].

Our purpose is to study, through the case of a patient operated for right hepatic tumour, the clinical, radiological, anatomopathologic and therapeutic aspects of the peripheral primitive neuroectodermal tumours (PPNET). This tumour (PPNET) is a neoplasm belonging to the Ewing's family tumours, whose histology is similar. Its diagnosis requires the contribution of histopathology, immunohistochimy and cytogenetic studies. The primary hepatic localization of this rare tumour (our case), has never been reported. The treatment, in theory copied on that of the Ewing's sarcoma, is complex and not yet codified, which makes it another disappointing aspect of this disease whose prognosis remains dark.

Diagnosis, Differential↗
PubMed1988

Chromosome abnormalities in pediatric brain tumors.

Recurrent, site-specific chromosome translocations and other cytogenetic abnormalities are being described in ever-increasing numbers and types of human tumors. Primary brain tumors are the most common pediatric solid tumor and differ from those of adults in both histology and clinical behavior. We examined chromosomes from 21 primary pediatric brain neoplasms grown in short-term tissue culture, including 6 astrocytomas, 10 primitive neuroectodermal tumors, and 5 other tumors. Karyotypes from 3 of 5 astrocytomas were abnormal, as were those of 9 of 10 primitive neuroectodermal tumors. Numerical abnormalities were found in 6 tumors and structural aberrations in 12 tumors. Deletions, additions, and translocations involving the short arm of chromosome 1 were observed in 5 tumors, with chromosome breakpoints ranging from 1p1 to 1p3. An isochromosome of the long arm of 17, i(17q) was the most frequent site-specific structural abnormality, found in 1 anaplastic astrocytoma and 2 recurrent cerebellar primitive neuroectodermal tumors, one with islands of anaplastic astrocytoma. These results differ from reported chromosome studies of adult brain tumors, suggesting that pediatric brain tumors may differ from those of adults when examined at the genetic level. Additional chromosomal and molecular studies of brain tumors from children are warranted to define these differences.

Adolescent↗
PubMedDate not supplied

Extracellular matrix of small round cell tumors of childhood: an immunohistochemical study of 67 cases.

Sixty-seven childhood tumors were studied immunohistochemically for the extracellular matrix element type IV collagen, laminin, and fibronectin. Tumors included Ewing's sarcoma, primitive neuroectodermal tumor, small cell osteosarcoma, neuroblastoma or ganglioneuroblastoma, rhabdomyosarcoma, and lymphoma. It was found that small cell osteosarcoma was often positive for fibronectin but not type IV collagen or laminin, a new observation. In the lymphomas, matrix proteins were rarely found. Ewing's sarcoma was variably positive for type IV collagen and laminin, but fibronectin was absent. Extracellular laminin and fibronectin were found in one of two cases of primitive neuroectodermal tumor. In neuroblastoma and ganglioneuroblastoma, the matrix components were rarely found. These results, discrepant with findings in cultured cells, may reflect the altered capacity of tumors to produce these proteins in vitro, which suggests that caution should be exercised in drawing conclusions regarding the nature or histogenesis of tumors from data obtained with cultured tumor cells. Embryonal rhabdomyosarcoma frequently contained all matrix elements in the extracellular space and in a dotlike pattern in the cytoplasm; alveolar rhabdomyosarcoma rarely contained these proteins and never exhibited the dotlike pattern. The frequent finding of matrix proteins in embryonal rhabdomyosarcoma but only rarely in alveolar rhabdomyosarcoma and the unique immunostaining pattern in embryonal rhabdomyosarcoma may prove to be a useful adjunct in the diagnosis of childhood tumors.

Adolescent↗
PubMed1984

Neuroectodermal tumor and monoclonal antibodies.

Antibody-producing clones were obtained by hybridization of spleen cells from mice immunized with whole cultured human tumor cells and mouse myeloma cells, P3UX59AG8. The tumor cells were derived from a peripheral primitive neuroectodermal tumor. One of the antibodies produced by these clones reacts with the original cell line, SK-PN-DW, and other more differentiated neuroectodermal tumors such as neuroblastomas and melanomas. The cell line SK-PN-DW contains antigenic determinants recognized by monoclonal antibodies raised against melanoma, neuroblastoma, and human fetal brain. These data indicate that this primitive neuroectodermal tumor is derived from the neuroectoderm.

Adolescent↗
PubMed2005

Primitive supratentorial neuroectodermal tumor in an adult.

We report the case of a 32-year-old female with a diagnosis of supratentorial tumour. Total removal of the tumour was achieved in a two-stage procedure. Histopathology revealed a primitive neuroectodermal tumour (PNET), an unusual and highly malignant, mainly infratentorial tumour of childhood that is uncommonly described in the supratentorial compartment of adults. We review the literature and describe the existing knowledge of these tumours.

Adult↗
PubMed1997

Parental occupation, occupational exposure to solvents and polycyclic aromatic hydrocarbons and risk of childhood brain tumors (Italy, France, Spain)

The role of parental occupational exposure in childhood brain tumors was investigated in a population-based case-control study grouping 251 cases and 601 controls from three European centers: Milan (Italy), Paris (France), and Valencia (Spain). Parental occupational exposure to solvents and polycyclic aromatic hydrocarbons (PAH) during the five-year period before birth was estimated using a job-exposure matrix developed earlier in the same countries. Odds ratios (OR) of brain tumors for each occupation and occupational exposure were estimated by logistic regression, adjusting for child's age, gender, exposure to tobacco smoke and ionizing radiation, mother's age and years of schooling, and center. The risk of childhood brain tumors rose when fathers worked in agriculture (OR = 2.2, 95 percent confidence interval [CI] = 1.0-4.7) and motor-vehicle-related occupations. In the latter group, the risk increased for primitive neuroectodermal tumors in particular (OR = 2.7, CI = 1.1-6.6). Astroglial tumors were more frequent among children of mothers in health services (OR = 2.2, CI = 1.0-4.9). Paternal exposure to PAHs was associated with an increased, but not dose-related, risk of primitive neuroectodermal tumors (OR = 2.0, CI = 1.0-4.0), and maternal exposure to solvents at a high level was associated with an increased risk of both astroglial (OR = 2.3, CI = 0.9-5.8) and primitive neuroectodermal tumors (OR = 3.2, CI = 1.0-10.3).

Adolescent↗
PubMed1991

Nerve growth factor receptor expression in peripheral and central neuroectodermal tumors, other pediatric brain tumors, and during development of the adrenal gland.

Nerve growth factor (NGF) is important to the survival, development, and differentiation of neurons. Its action is mediated by a specific cell surface transmembrane glycoprotein, nerve growth factor receptor (NGFR). In this study, NGFR expression by human fetal and adult adrenal medullary tissue, peripheral nervous system (PNS) neuroectodermal tumors (neuroblastoma, ganglioneuroblastoma, ganglioneuroma), pediatric primitive neuroectodermal tumors (PNETs) of the central nervous system (CNS), and CNS gliomas was examined by an immunohistochemical technique. Sixty-nine tumors in total were probed in this manner. Nerve growth factor receptor immunoreactivity was confined to nerve fibers and clusters of primitive-appearing cells in the fetal adrenal, and to nerve fibers and ganglion cells of the adult adrenal medulla; adrenal chromaffin cells were negative. In PNS neuroectodermal tumors, there was NGFR expression in tumor cells of 6 of 11 neuroblastomas and 6 of 6 ganglioneuroblastomas or ganglioneuromas. Thirteen of thirty-five CNS PNETs showed NGFR positivity. In most CNS PNETs, NGFR was restricted to scattered single or small groups of cells, but two tumors with astroglial differentiation showed much more extensive immunoreactivity. Most astrocytomas (11 of 14) and all ependymomas (3 of 3) were intensely NGFR positive.

Adolescent↗