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Results for “Neuroectodermal Tumors, Primitive, Peripheral”

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At least 955 records · Page 53Linked to original sources
PubMed2000

Dysembryoplastic neuroepithelial tumor: an immunohistochemical study with myelin oligodendrocyte glycoprotein.

CONTEXT: The dysembryoplastic neuroepithelial tumor (DNT) is an uncommon lesion characterized by a heterogeneous population of neurons, astrocytes, and oligodendroglia-like cells (OLCs). The basic nature of the DNT and its constituent cells, particularly the OLCs, remains unresolved; some authors favor a neuronal origin, and others propose a glial or mixed origin for these cells. DESIGN: We examined 11 DNTs with antibodies to myelin oligodendrocyte glycoprotein, a marker of mature oligodendrocytes. RESULTS: All DNTs studied (7 from males, 4 from females; age range of patients, 2-37 years) were composed of varying proportions of neurons, astrocytes, and OLCs. Membrane or cytoplasmic immunoreactivity for myelin oligodendrocyte glycoprotein was found in many OLCs in 9 of 11 cases. The number of myelin oligodendrocyte glycoprotein-positive OLCs was variable: >75% of the OLCs were positive in 5 cases, 25% to 75% of the OLCs were positive in 2 cases, and <25% of the OLCs were positive in 2 cases. CONCLUSION: These findings suggest that many of the OLCs represent mature oligodendrocytes and support the notion that DNTs are heterogenous lesions composed of multiple, mature cell types.

Adolescent↗
PubMed2006

Molecular diagnosis of sarcomas: chromosomal translocations in sarcomas.

CONTEXT: Sarcomas are rare, numerous in type, and often difficult to definitively classify. Work in the last 2 decades has revealed that a significant subset of sarcomas are associated with specific chromosomal translocations producing chimeric (fusion) genes that play a role in the sarcomas' biology and are helpful in their differential diagnosis. OBJECTIVE: To briefly review the sarcomas associated with specific translocations presenting Ewing sarcoma and synovial sarcoma as archetypes and to further explain how cytogenetic and molecular biologic approaches are being used in the diagnosis of sarcomas. DATA SOURCES: This work is based on a selected review of the relevant medical and scientific literature and our extensive experience with molecular testing in sarcomas. CONCLUSIONS: In addition to, and complementing, the traditional diagnostic methods of examination of hematoxylin-eosin stained slides, immunohistochemistry, and sound clinical-pathologic correlation, additional cytogenetic and molecular biologic methods are being increasingly utilized and relied on in sarcoma pathology. These methods include chromosomal karyotyping, fluorescence in-situ hybridization, spectral karyotyping, and polymerase chain reaction- based methods for demonstrating specific chromosomal translocations and fusion genes. Understanding the basis of these methods and their application is critical to better provide accurate and validated specific diagnoses of sarcomas.

Bone Neoplasms↗
PubMed1999

Increased oncogenicity of subclones of SV40 large T-induced neuroectodermal tumor cell lines after loss of large T expression and concomitant mutation in p53.

A model for medulloblastoma-like primitive neuroectodermal tumors was established in rat using retrovirally transduced SV40 large T antigen (LT) as an inducing agent (O. D. Wiestler et al., Brain Pathol., 2: 47-59, 1992). A cell line isolated from such a tumor and clonal derivatives thereof were biologically and molecularly characterized. In the parental tumor cell line, TZ870, which had been selected for G418 resistance, virtually all cells expressed LT and wild-type p53, which were complexed to each other. When plated in soft agar, these cells grew relatively slowly and formed disperse colonies. However, when grown without selection pressure, these cells reproducibly gave rise to LT-negative and G418-sensitive derivatives, LT-0 cells. Surprisingly, these latter cells exhibited a higher degree of malignancy both in vitro, growing readily to large colonies in soft agar, and in vivo, where they gave rise to a rapidly growing malignant tumor. Clonal selection from TZ870 cells revealed two types of clones: in one type, LT expression was stably maintained, even without selection pressure, whereas the other type lost the LT coding sequences. All LT-negative clones exhibited the same phenotype as the LT-0 cells. Reexpression of LT had no effect. However, LT no longer formed complexes with p53, and p53 was metabolically stable, suggesting that it had been mutated. Sequence analyses and diagnostic restriction digests of the p53 gene revealed that (a) both the parental LT-transformed cells and their derivatives contained only one complete p53 allele and (b) all LT-positive clones expressed wild-type p53, whereas all LT-negative clones expressed a mutant allele with a common mutation at Cys-174-->Tyr, indicating their clonal origin. We assume that the loss of LT coding sequences is the consequence of the p53 mutation, perhaps by inducing genomic instability, and that both the p53 mutation and additional genetic alterations that accompany the loss of LT coding sequences might contribute to enhanced malignancy.

Animals↗
PubMed1976

Dictyoma.

Explore the source record for details and available documents.

Child, Preschool↗
PubMed1999

[Malignant small-cell thoracic pulmonary tumor (Askin tumor)].

We report 4 cases of malignant thoraco-pulmonary small-cell tumors (Askin tumor). Only two cases were operated. We emphasize the difficult histological diagnosis and demonstrate the importance of complete removal for survival. Prognosis remains poor.

Adolescent↗
PubMedDate not supplied

[Plastic repair of a defect in the base of the skull with soft tissues from the orbit after the removal of an extensive esthesioneuroepithelioma].

The paper describes a clinical observation of closure of sphenoidal sinus defect and plastic repair of dura mater by using orbital tissues after removal of a tumor from the medial portions of the middle cranial fossa, which spread into the orbit and sphenoidal sinus, in complete irreversible loss of visual function, ophthalmoplegia and ptosis in a patient with skull soft tissue hypotrophy due to multiple operations and radiation therapy and hence unsuitable for displacement and closure. This observation shows it possible to use orbital soft tissue for repair of the base of the skull, in cases when integumentary cranial tissues are impossible to use as a plastic material due to their hypotrophicity. At the same time severe dysfunctions, such as blindness and ophthalmoplegia enable orbital tissues to be employed without significantly deteriorating any functional and cosmetic effect.

Adult↗
PubMed1999

EWS/ETS fusion genes induce epithelial and neuroectodermal differentiation in NIH 3T3 fibroblasts.

Ewing's sarcoma is the least differentiated member of the peripheral primitive neuroectodermal (pPNET) tumor family. Chromosomal translocations involving the EWS gene and five different Ets family transcription factor genes create fusion genes encoding aberrant transcription factors and are implicated in the vast majority of Ewing's sarcoma cases. Here, NIH 3T3 fibroblasts were infected with control (tk-neo or RAS) and two different EWS/ETS-expressing retroviruses. In vitro studies of established polyclonal lines expressing the two EWS/ETS genes, either EWS/FLI1 or EWS/ETV1, showed induction of cytokeratin 15 gene expression. Both fusion genes also caused characteristic gross morphologic, histologic, and ultrastructural changes in NIH 3T3 cells when transformed cell lines were injected into CB-17-scid mice. Native NIH 3T3 cells with a spindled cell morphology were converted to polygonal cells with high nucleo-cytoplasmic ratios that continued to express abundant cytokeratin. Extracellular collagen deposition was abolished, rough endoplasmic reticulum was markedly diminished, and rudimentary cell-cell attachments appeared. Most strikingly, neurosecretory-type dense core granules like those seen in pPNET were now evident. This murine model, created in mesenchyme-derived NIH 3T3 cells, demonstrated new characteristics of both neuroectodermal and epithelial differentiation and resembled small round cell tumors microscopically.

3T3 Cells↗
PubMed2000

Induction of cell death by basic fibroblast growth factor in Ewing's sarcoma.

Ewing's sarcoma is thought to arise after developmental arrest of primitive neural cells during embryogenesis. Because basic fibroblast growth factor (bFGF) has a critical role in the regulation of cell survival, proliferation, and differentiation during embryogenesis, we have tested the hypothesis that bFGF and FGF receptors may contribute to the development of Ewing's sarcoma and may provide a mechanism for the modulation of their behavior. All four of the Ewing's sarcoma cell lines examined expressed bFGF and FGF receptors, which were detected by immunofluorescence and Western blotting. bFGF-induced a significant dose-dependent decrease in Ewing's sarcoma cell proliferation on plastic and reduced anchorage-independent growth in soft agar. Unexpectedly, this decrease in cell number reflected bFGF-induced apoptosis and necrosis, as demonstrated by electron microscopy, binding of annexin V, and staining with acridine orange. Induction of cell death was dependent on dosage of, and period of exposure to, bFGF. bFGF did not induce differentiation of Ewing's sarcoma cells in either the presence or the absence of serum or nerve growth factor. Treatment of NuNu mice with bFGF decreased growth of the highly tumorigenic Ewing's sarcoma cell lines. Histologically tumors grown in the NuNu mice treated with bFGF were less cellular than those in control mice, and showed an increased level of apoptotic nuclei. This is in contrast to the mitogenic effect bFGF has in most other cancer cells. In summary, bFGF decreases Ewing's sarcoma growth in vitro and in vivo by the induction of cell death. This novel observation may provide a new therapeutic strategy for Ewing's sarcomas.

Animals↗
PubMed2000

Epithelial tumors of the lung.

Our knowledge and understanding of bronchopulmonary tract tumors have grown considerably; modern pathology enables the phenotyping of many tumors with increasingly improving techniques and tools and, arguably, improving criteria. By the same token, at least some of the new data may not be readily grafted onto traditional classification schemes. Some traditional designations will be dropped and replaced. And, although it has been overenthusiastically argued that molecular classifications may be attained, that ideal might not be truly an improvement. For classifications to be useful, they should be relatively simple, easily reproducible, and clinically significant. Still, modern marker pathology has revealed new vistas for the evaluation, diagnosis, and therapy of at least some tumors. These developments merit optimism but also caution from clinicians and pathologists.

Adenocarcinoma↗