Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0079731 (B-cell lymphoma)
 16,671 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Introduction and expression of the proto-oncogene bcl-2 (B-cell lymphoma/leukemia 2) has been shown to extend the survival of certain hematopoietic cell lines after growth factor deprivation, by blocking apoptosis or programmed cell death. We investigated the effect of bcl-2 expression on cellular sensitivity to lysis by tumor necrosis factor (TNF), a cytokine capable of inducing apoptosis in several tumor cell lines. Introduction of the human bcl-2 gene in the highly TNF-sensitive L929 mouse fibrosarcoma cell line did not result in altered TNF sensitivity. Likewise, NIH3T3 and REF cells, which are resistant to TNF cytotoxicity but become TNF sensitive upon cotreatment with actinomycin D or upon expression of the adenovirus E1A gene, did not show altered TNF sensitivity upon bcl-2 transfection. Despite constitutive expression of the endogenous bcl-2 gene, human MCF7 breast carcinoma cells, as well as HL60 promyelocytic leukemia and U937 histiocytic lymphoma cell lines were found to be TNF sensitive. bcl-2-overexpressing derivatives of these cell lines did not acquire reduced TNF sensitivity and still exhibited the characteristic pattern of internucleosomal DNA fragmentation of TNF-induced apoptosis. Moreover, bcl-2 expression in the interleukin 3 (IL-3)-dependent myeloid cell line 32D protected these cells from apoptosis resulting from growth factor deprivation, but not from apoptosis induced by TNF. These data clearly establish the absence of a correlation between bcl-2 gene expression and cellular sensitivity to TNF-induced cell lysis. These findings are discussed in the context of the hypothesis of different pathways for induction of apoptosis, only some of which are affected by bcl-2 expression.
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PMID:Effect of bcl-2 proto-oncogene expression on cellular sensitivity to tumor necrosis factor-mediated cytotoxicity. 845 35

True histiocytic lymphoma is considered a rare entity, and its diagnosis requires the concordance of morphological, immunophenotypic, and molecular findings. The association of malignant lymphoma with tumors in the monocyte-macrophage system has rarely been described. We present a case of mucosa-associated lymphoid tissue (MALT)-type low-grade B-cell lymphoma of the stomach, contiguous to a large tumoral mass that fulfills the morphological criteria (large cells with abundant pale cytoplasm and lobulated or kidney-shaped nuclei) and immunophenotypical features (human leukocyte antigen-DR locus, CD68, S-100, lysozyme immunoreactivity, and negative B- and T-cell markers) required for the diagnosis of histiocytic lymphoma. The patient remains in complete remission 18 months after surgery. The association of low grade-malignant lymphoma with tumors of monocyte-macrophage system cells is an exceedingly rare phenomenon. Whether these tumors are directly related or occur due to pure chance requires the identification of new cases and further study.
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PMID:True histiocytic lymphoma of the stomach associated with low-grade B-cell mucosa-associated lymphoid tissue (MALT)-type lymphoma. 889 46

Vi bacterial polysaccharide is a homopolymer of alpha 1-4 N-acetyl polygalacturonic acid with variable O-acetylation at position C-3 and forms a capsule around many bacteria. It has been referred to as the virulence factor of Salmonella typhi and is also a candidate vaccine against typhoid fever. The present study reports the interaction of this polysaccharide with murine mononuclear phagocytes and lymphocytes, and with human monocytes. Vi showed a dose-dependent binding to the murine monocyte cell lines WEHI-274.1 and J774. This binding was abrogated if the polysaccharide was deacetylated, suggesting involvement of acetyl groups in this interaction. Vi also bound to the murine B-cell lymphoma line A20, to peritoneal exudate cells and to a lesser degree to spleen cells and thymocytes from BALB/c mice. The polysaccharide also interacted with the human histiocytic lymphoma line U937 but not with the human monocyte cell line THP-1. Stimulation with Vi led to up-regulation of surface major histocompatibility complex (MHC) class II expression on A20 cells. Immunoprecipitation of Vi-bound molecules from cell surface biotinylated A20 and WEHI-274.1 revealed two bands with MW of about 32,000 and 36,000. The study demonstrates that Vi capsular polysaccharide can interact with mononuclear phagocytes and lymphocytes through specific cell surface molecules and modulate MHC class II expression.
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PMID:Identification of specific recognition molecules on murine mononuclear phagocytes and B lymphocytes for Vi capsular polysaccharide: modulation of MHC class II expression on stimulation with the polysaccharide. 937 Sep 37

This is the second report of histiocyte-rich B-cell lymphoma and the first case analyzed by flow cytometry and cytogenetic study. The immunophenotype determined by flow cytometry was that of a B-cell antigen-positive, surface immunoglobulin-negative B-cell lymphoma with 79% CD11c positive histiocytes. The lymphoid cells were composed of 76% neoplastic B-cells and 24% reactive T-cells. Immunohistochemical staining showed large numbers of histiocytes positive for CD68 and lysozyme in the lymph node and the bone marrow. Neoplastic lymphoid cells were positive for CD20, CD45, CD74 and CDw75. The monoclonality of the tumor cells was established by the evidence of rearrangements of the heavy chain and kappa light chain genes and a complex clonal cytogenetic abnormalities including t(8;14)(q11;q32). The tumor cells were large, pleomorphic lymphoid cells and showed no features resembling those of the L/H cells of Hodgkin's disease as previously reported. The rapidly progressive clinical course in the present case is consistent with the clinical features shown in the original study. The histiocytic component in this tumor is presumably recruited by a lymphokine with the nature of a growth factor from the tumor cells that may also be responsible for the rapid proliferation of the tumor cells and the aggressive clinical course. This entity merits special recognition because it leads to a predictable poor prognosis and because of its potential of being misdiagnosed as true histiocytic lymphoma.
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PMID:Histiocyte-rich B-cell lymphoma. 938 44

The bcl-2 proto-oncogene encodes an inner mitochondrial membrane protein that blocks apoptosis and programmed cell death in human lymphoid tissue. In this study a monospecific anti-human bcl-2 antibody that is reactive in formalin-fixed tissues was used with an avidin-biotin complex immunoperoxidase method to evaluate 41 cases of lymphoproliferative disorders of the salivary gland. The study cases were 26 primary salivary gland lymphomas (including 21 B-cell lymphomas four T-cell lymphomas and one true histiocytic lymphoma) and 15 cases of myoepithelial sialadenitis. Bcl-2 expression is restricted to the mantle zone and interfollicular lymphocytes around reactive germinal centers of myoepithelial sialadenitis. Seventeen of the 21 B-cell lymphomas were positive for bcl-2, and were composed of mucosa-associated lymphoid tissue (MALT), centrocytic, centroblastic-centrocytic and centroblastic lymphomas. Noticeably, all 11 cases of MALT lymphoma were bcl-2 positive. In contrast, staining for bcl-2 was present in only one of four cases of T-cell lymphomas and was negative in one true histiocytic lymphoma. The expression of bcl-2 protein was also investigated in the ductal systems and epimyoepithelial islands of salivary glands from patients with malignant lymphoma and myoepithelial sialadenitis. While salivary ducts in eight of 15 cases of myoepithelial sialadenitis immunostained for bcl-2, epimyoepithelial islands showed bcl-2 expression in only five cases of myoepithelial sialadenitis. We found that ductal cells in the salivary gland from patients with primary non-Hodgkin's lymphomas expressed bcl-2 protein. It was of interest that epimyoepithelial islands in all cases of MALT lymphoma displayed bcl-2 expression whereas other subtypes of B-cell lymphoma, T-cell lymphoma and true histiocytic lymphoma were invariably negative. These results indicate that bcl-2 is expressed in a wide variety of non-Hodgkin's lymphomas, especially when all 11 cases of MALT lymphoma are bcl-2 positive. Epimyoepithelial islands in MALT lymphoma express this oncoprotein, and their ability to induce bcl-2 synthesis resulted in the prevention of apoptosis and prolonged cell survival. Furthermore, the expression of bcl-2 protein in the lymphoma cells may be responsible for the induction of bcl-2 expression in the adjacent epimyoepithelial islands through a lymphocyte chemical mediator.
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PMID:Detection of the apoptosis-suppressing oncoprotein bcl-2 in salivary gland lymphoma. 958 34


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