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

Epstein-Barr virus, the apparent cause of infectious mononucleosis, may also be an etiological agent in nasopharyngeal carcinoma and Burkitt's lymphoma. Lymphocytes from normal individuals with anti-Epstein-Barr virus antibody activity may be sensitized to Epstein-Barr virus and contain transfer factor with the potential to program and/or recruit other lymphocytes to react against the virus and/or viral antigens. A patient with nasopharyngeal carcinoma refractory to conventional therapy was treated with transfer factor obtained from normal, young adults with previous history of infectious mononucleosis. Following immunotherapy, apparent slowing of tumor growth was observed, which was associated with intense lymphocytic infiltration of the tumor and reconstitution of delayed cutaneous hypersensitivity reactions to microbial recall antigens. A double-blind randomized clinical trial has been initiated to determine whether transfer factor immunotherapy is a useful adjunct to radiotherapy in the primary treatment of patients with nasopharyngeal carcinoma. If successful, a similar trial might be considered for African patients with Burkitt's lymphoma.
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PMID:In vivo and in vitro studies of immunotherapy of nasopharyngeal carcinoma with transfer factor. 125 57

Lymph node biopsies of 52 patients with Hodgkin's disease were analyzed by Southern blot hybridization for the presence of monoclonal rearrangements of immunoglobulin and T cell receptor genes. The same tissues were tested for Epstein-Barr virus DNA by the polymerase chain reaction using four different sets of primers. Monoclonal rearrangements were identified in only four tumors, whereas Epstein-Barr virus was present in 79% of biopsies. A correlation between the degree of infiltration by Reed-Sterberg cells, clonality and the presence of Epstein-Barr virus could not be found. These results are in agreement with similar studies reported in the literature. The nature of the malignant cell in Hodgkin's disease and the role of Epstein-Barr virus in the etiology of this tumor remains to be established.
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PMID:[Demonstration of Epstein-Barr virus DNA and determination of immunoglobulin and T-cell receptor gene rearrangerments in diagnostic lymph node biopsies from patients with Hodgkin's disease]. 128 55

In a series of 33 cynomolgus monkeys (Macaca fascicularis) experimentally infected with Simian Immunodeficiency virus (SIV), strain smm3, 13 animals developed malignant Non-Hodgkin lymphomas. These lymphomas presented with unusual primary manifestations like in the orbita, testes, and brain. The morphological features and immunophenotyping identified the tumors as high malignant B-cell lymphomas. In all tumors as well as in tumor-derived cell lines a cynomolgus B-lymphotropic herpes virus (CBLV) with structural homogeneity to the Epstein-Barr virus (EBV) could be demonstrated by Southern blotting with EBV-specific probes. The lymphoma cells also expressed CBLV-associated nuclear antigens involved in B-cell transformation crossreacting with EBNA-specific human sera and monoclonal antibodies. Ig-gene rearrangement studies revealed clonal populations, however, no translocations of the c-myc oncogene could be detected. The lymphomas developing with high frequency in SIV-induced immunodeficiency resemble a major subtype of human EBV-associated AIDS lymphomas. This animal model can therefore be used to further elucidate interactions of HIV and EBV in AIDS-related lymphomagenesis.
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PMID:[Opportunistic malignant lymphomas in SIV infected primates--a model for Epstein-Barr virus associated lymphomas in AIDS]. 128 56

72 T-cell lymphomas were analyzed for the presence of Epstein-Barr virus DNA using Southern or dot blot hybridization. EBV DNA was found in 25 peripheral T-cell lymphomas and in none of 6 T-lymphoblastic tumors. A high prevalence of EBV was detected in AILD type, Lennert's, pleomorphic medium and large cell nodal lymphomas and in upper aerodigestive tract lymphoma biopsies. Clonotypic analysis revealed monoclonal as well as oligoclonal viral populations. The possible influence of EBV in lymphomagenesis, the impact of virus-mediated interactions in the B- and T-cell system and factors involving site of tumor development are discussed.
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PMID:[Detection of Epstein-Barr virus genomes in various entities of low and high grade T-cell lymphomas]. 128 58

Fourty-three primary cerebral lymphomas (PCL) were histologically classified and examined for genome expression of Epstein Barr Virus (EBV) and human herpes virus 6 (HHV6) using dot blotting, polymerase chain reaction, and Southern blotting. Only 20 tumors (16 high grade and 4 low grade lymphomas) could be suitably placed into a category of the Updated Kiel Classification, whereas the non-classified 23 tumors were highly malignant B-lymphomas and referred to as small-cell (SC) or large-cell (LC) blastic PCL. Most of the LC PCL showed a tumor-like infiltration pattern with high cellular density and little remaining parenchyma, whereas the SC PCL more often showed an inflammation-like pattern characterized by loose arrangement of tumor cells and marked astrocytic, microglial and T-lymphocytic reaction. EBV genome was found in 3/3 AIDS cases, but in none of 40 immunocompetent cases, while HHV6 was detected in 2 tumors of immunocompetent patients. We conclude that (1) the Updated Kiel Classification is not applicable to a majority of PCL, and (2) EBV and HHV6 do not appear to play a major role in the pathogenesis of PCL in immunocompetent subjects.
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PMID:[Classification and virus expression of primary cerebral lymphomas]. 128 60

In recent years, techniques, probes, and reagents became available to reliably visualize individual Epstein-Barr virus (EBV)-infected cells, to assess EBV gene expression, and to analyze the clonal composition of EBV genomes in human tissues. Application of these techniques to more than 1000 lymphoid tissue specimens revealed (1) characteristic cellular and compartmental distribution patterns of EBV-infected cells in normal lymph nodes, reflecting the interference of EBV with physiologic B cell differentiation pathways, (2) an association of EBV with various mono- and oligoclonal lymphoproliferations ranging from benign conditions to overtly malignant lymphomas, and (3) characteristic patterns of EBV gene expression among EBV-associated lymphoproliferations. In the context of the established immortalizing and transforming properties of EBV, the findings support the concept of an etiologic role of EBV for cases of certain lymphomas such as Burkitt's lymphoma, anaplastic large cell lymphoma, Hodgkin's disease, and lymphomas arising in immunocompromised individuals. In contrast, lymphomas harboring EBV in only proportions of the tumor cells (such as cases of peripheral T cell lymphoma and some B cell lymphoma types) argue against an etiologic role in the primary process of malignant transformation for the virus in these instances. Since in many of these cases a proportion of the EBV infected tumor cells express the EBV oncoprotein LMP (latent membrane protein) the virus may influence, however, the proliferative properties as well as the morphological and molecular phenotype of the neoplastic cells.
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PMID:[Epstein-Barr virus associated lymphocyte proliferation]. 128 80

Interferon gamma (IFN-gamma) production has been attributed exclusively to activated T cells and NK cells. We sought to determine whether human B cells express IFN-gamma. We studied 28 B cell lines including Epstein-Barr virus (EBV)+ normal lymphoblastoid B cell lines (N = 7), EBV+ B cell lines derived from patients with Burkitt's lymphoma with (N = 6) or without AIDS (N = 8), as well as seven EBV- B cell lines. All cell lines were studied by reverse transcription-polymerase chain reaction (RT-PCR). We detected constitutive expression of IFN-gamma in every B cell line. The tumor promoters PMA and teleocidin appeared to enhance this IFN-gamma expression in nearly every B cell line. The 517 bp amplicons spanning the entire protein coding region of the IFN-gamma mRNA from three representative lines were sequenced, definitively establishing that B cell IFN-gamma is identical to IFN-gamma from activated T cells and is not altered by derivation of the B cell lines from AIDS patients or by EBV status. Detection of IFN-gamma in the entire panel of EBV+ and EBV- cell lines suggests that the IFN-gamma gene is broadly expressed by human B cells. Our data imply that human B cells can be activated to produce IFN-gamma, further enmeshing B cells in the dynamics of immunoregulation.
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PMID:Human B cell lines express the interferon gamma gene. 129 29

Nasopharyngeal carcinoma (NPC) is the third most common cancer in the southern provinces of China, but a rare cancer in other parts of the world. Epidemiological studies suggested a multifactorial etiology of NPC involving infection of Epstein Barr virus (EBV), genetic predisposition, environmental factors, such as consumption of salted fish, and other unknown factors. p53 mutation is a common event in many forms of human cancers but its possible involvement in the pathogenesis of NPC has not been examined. The presence of p53 mutation in NPC is studied by the sensitive PCR-SSCP analysis and direct DNA sequencing method. The frequent sites of p53 mutation (exons 4 to 8) reported in other human tumors were studied. Thirty-eight biopsied tumors of NPC and 4 NPC cell lines were examined for the presence of p53 mutation. No mutation of p53 resulting in change in amino acid sequence of the encoded p53 protein was identified in any of the biopsies tumors. RFLP studies of the biopsied materials of NPC also revealed no loss of heterozygosity at chromosome region 17p13 in 15 out of 15 informative cases, which further supports the conclusion that p53 mutation is an infrequent event in NPC. Apparently, p53 mutation has no significant role in the pathogenesis of this special group of human cancers. However, p53 mutation is frequently observed in cell lines derived from the primary NPC tumors. All the three NPC cell lines examined carry a missense p53 mutation, suggesting that mutation of the p53 gene may confer growth advantage to the tumor cells to become established in culture.
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PMID:p53 mutation in human nasopharyngeal carcinomas. 129 43

Previous studies on Epstein-Barr virus (EBV)-positive B-cell lines have identified two distinct forms of virus latency. Lymphoblastoid cell lines generated by virus-induced transformation of normal B cells in vitro, express the full spectrum of six EBNAs and three latent membrane proteins (LMP1, LMP2A, and LMP2B); furthermore, these lines often contain a small fraction of cells spontaneously entering the lytic cycle. In contrast, Burkitt's lymphoma-derived cell lines retaining the tumor biopsy cell phenotype express only one of the latent proteins, the nuclear antigen EBNA1; such cells do not enter the lytic cycle spontaneously but may be induced to do so by treatment with such agents as tetradecanoyl phorbol acetate and anti-immunoglobulin. The present study set out to determine whether activation of full virus latent-gene expression was a necessary accompaniment to induction of the lytic cycle in Burkitt's lymphoma lines. Detailed analysis of Burkitt's lymphoma lines responding to anti-immunoglobulin treatment revealed three response pathways of EBV gene activation from EBNA1-positive latency. A first, rapid response pathway involves direct entry of cells into the lytic cycle without broadening of the pattern of latent gene expression; thereafter, the three "latent" LMPs are expressed as early lytic cycle antigens. A second, delayed response pathway in another cell subpopulation involves the activation of full latent gene expression and conversion to a lymphoblastoidlike cell phenotype. A third response pathway in yet another subpopulation involves the selective activation of LMPs, with no induction of the lytic cycle and with EBNA expression still restricted to EBNA1; this type of latent infection in B lymphocytes has hitherto not been described. Interestingly, the EBNA1+ LMP+ cells displayed some but not all of the phenotypic changes normally induced by LMP1 expression in a B-cell environment. These studies highlight the existence of four different types of EBV infection in B cells, including three distinct forms of latency, which we now term latency I, latency II, and latency III.
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PMID:Three pathways of Epstein-Barr virus gene activation from EBNA1-positive latency in B lymphocytes. 130 42

Severe combined immunodeficient (SCID) mice reconstituted with lymphocytes from Epstein-Barr virus (EBV) negative human donors develop aggressive tumors after the chimeric mice are infected with EBV. The tumors were composed of human B cells that expressed EBV encoded antigens (latent membrane protein and EBV nuclear antigen2). Southern blot analysis of DNA from 16 SCID/hu tumors with human Ig gene probes showed that each tumor contained multiple heavy and light chain gene rearrangements. Ig kappa gene rearrangements were frequent, while clonal lambda gene rearrangements were infrequent. Analysis of EBV terminal repeat sequences indicated two or more fused termini in each tumor, consistent with a multiclonal origin. Linear terminal repeat segments and viral antigens (EA-D and EA-R) associated with EBV replication were not detected in the tumors. High levels of human Igs in the SCID/hu serum were oligoclonal and primarily contained kappa light chains. Before the appearance of overt tumors, circulating cells with human and EBV DNA could be detected in the SCID/hu mice by the polymerase chain reaction. We conclude that EBV infection in SCID/hu chimeric mice produces a limited number of transformation events, which give rise to oligoclonal tumors resembling EBV-associated lymphoproliferative disorders in some immune-deficient patients.
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PMID:Epstein-Barr virus induced lymphoproliferative tumors in severe combined immunodeficient mice are oligoclonal. 130 25


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