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)

The translocation t(2;5), which leads to the fusion of the nucleophosmin gene (NPM) on chromosome 5q35 to the receptor kinase ALK on chromosome 2p23, is found in CD30+ anaplastic large cell lymphomas and some cases of B-cell lymphoma. Hodgkin's disease (HD) is a malignant lymphoma characterized by large multinucleated tumour cells, Hodgkin and Reed-Sternberg (H&RS) cells, surrounded by a dense lymphohistiocytic infiltrate. Our group recently demonstrated NPM/ALK fusion cDNAs by single-cell RT-PCR in < 3% of CD30+ tumour cells in 2/9 cases of HD. To further delineate the relevance of this finding for HD, we studied the occurrence of NPM/ALK fusion genes in peripheral blood cells of healthy donors by RT-PCR. NPM/ALK fusion cDNAs were found by RT-PCR in 14/29 healthy individuals and confirmed by hybridization with a breakpoint-specific oligonucleotide. Due to the low rate of NPM/ALK-positive cells in the peripheral blood of positive individuals, an assignment to a defined cellular subpopulation was not possible. We conclude that NPM/ALK fusion genes are present in peripheral blood cells of healthy donors. After t(14;18) and t(9;22), t(2;5) represents the third example of tumour-associated translocation products in blood cells of apparently healthy donors. The implications of this finding are discussed.
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PMID:Detection of the t(2;5)-associated NPM/ALK fusion cDNA in peripheral blood cells of healthy individuals. 988 32

T-cell lymphoma in patients infected with HIV is much less common than B-cell lymphoma. We describe two cases of HIV-associated extranodal lymphoma that showed Toutonlike tumor giant cells and mononuclear large lymphoma cells. Both cell types expressed T-cell-associated antigens, including CD3, CD5, CD43, and CD45RO, and were CD4- and CD30-positive and negative for all B-lineage-associated antigens. Both cases showed T-cell receptor gamma chain gene rearrangements using the polymerase chain reaction and were negative for the Epstein-Barr virus by in situ hybridization. Despite the expression of CD30 by the multinucleated cells, both cases were negative for ALK1 by immunohistochemistry and failed to show evidence of the nucleophosmin-anaplastic lymphoma kinase fusion product characteristic of t(2;5) using the reverse-transcriptase polymerase chain reaction. Although rare, CD4-positive, T-cell lymphoma with Toutonlike giant cells may be a distinct type of HIV-associated malignant lymphoma.
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PMID:Peripheral T-cell lymphoma with Toutonlike tumor giant cells associated with HIV infection: report of two cases. 1032 82

Tyrosine kinases causing the abnormal phosphorylation of intracellular proteins have been shown to contribute to oncogenic transformation in a number of human neoplasms. Immunohistological staining of routine biopsy sections for increased levels of phosphotyrosine may therefore provide a simple means of screening for tumours containing activated tyrosine kinases. In this study, monoclonal antibodies to phosphotyrosine were used to immunostain a cell line and tumour biopsies from lymphomas known to contain the activated anaplastic-lymphoma-kinase (ALK) tyrosine kinase. A range of normal and other neoplastic tissues were also immunostained for comparison. An anaplastic large cell lymphoma (ALCL) cell line carrying the (2;5) translocation, which creates the activated nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) tyrosine kinase, was strongly labelled. Routine tissue biopsies from five cases of ALK-positive ALCL were also strongly positive for phosphotyrosine. The characteristic granular cytoplasmic labelling pattern for phosphotyrosine observed in a B-cell lymphoma (expressing full length ALK kinase) was identical to that obtained using an ALK-specific antibody, thus confirming that labelling for phosphotyrosine in lymphoma cells reflects the presence of an activated kinase. When normal lymphoid tissues were stained, there was little or no labelling for phosphotyrosine, but stronger labelling was seen in other cells and tissues; for example, endothelial cells and some carcinoma samples. Whilst the strong labelling for phosphotyrosine observed in the lymphoma cells is due to the presence of activated ALK, the strong staining of some normal cells presumably represents physiologically active kinases and this should be taken into account when interpreting the immunostaining of non-lymphoid tumours. The simplicity of this method, however, means that it offers a new rapid approach to the screening of large numbers of tumours for the presence of aberrant tyrosine kinase activation, particularly if they arise from tissues which normally contain only background levels of phosphotyrosine.
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PMID:Immunohistochemical screening for oncogenic tyrosine kinase activation. 1039 26

Anaplastic large-cell lymphoma (ALCL) comprises approximately 25% of all non-Hodgkin lymphomas (NHL) in children and young adults, and up to 15% of high-grade NHL in older patients. Over 50% of these tumours carry the translocation t(2;5)(p23;q35). The result of this translocation is the fusion of the nucleophosmin (NPM) gene to the anaplastic lymphoma kinase (ALK) gene. The resulting hybrid protein contains the ALK catalytic domain that consequently confers transforming potential, which contributes to the pathogenesis of ALCL. To further analyse the transforming activity in an animal model, a cDNA encoding the protein product, NPM-ALK, was inserted into the retrovirus vector pLXSN and transduced into mouse bone marrow progenitors. These cells were subsequently used in a bone marrow transplant with the aim of reconstituting the haematopoietic compartments of lethally irradiated recipients. IL-9 transgenic mice were chosen as the animal model system, because dysregulated expression of the IL-9 gene in transgenic mice results in the sporadic development of spontaneous thymic lymphomas. Moreover, IL-9 is known to be expressed in cases of human ALCL. We used 15 IL-9 transgenic mice and eight corresponding wild-type mice (FVB/N) and transplanted them with NPM/ALK infected bone marrow cells. Eight IL-9 transgenic mice, serving as a control group, received pLXSN (vector only)-infected marrow. Reconstituted mice developed NPM-ALK-positive lymphomas, including lymphoblastic lymphomas of T-cell type (T-LB), mature and immature plasmacytoma (PC), and plasmoblastic/anaplastic diffuse large-B-cell lymphoma after about 19-20 weeks. The combined overexpression of NPM-ALK and IL-9 led to the transformation of murine lymphoid cells with accelerated and enhanced development of T-LB in 46% of the mice, which only very rarely occurs in IL-9 transgenic mice only. Of the 15 animals, five (33%) developed plasmacytic/plasmoblastic neoplasms, of which the most aggressive tumours share many features with anaplastic/plasmoblastic diffuse large-B-cell lymphoma on the basis of morphology, a characteristic growth pattern and ALK expression.
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PMID:Overexpression of NPM-ALK induces different types of malignant lymphomas in IL-9 transgenic mice. 1255 65

Anaplastic large cell lymphomas (ALCLs) are caused by chromosomal translocations that juxtapose the anaplastic lymphoma kinase (ALK) proto-oncogene to a dimerization partner, resulting in constitutive expression of ALK and ALK tyrosine kinase activity. One substrate of activated ALK in human ALCLs is the transcription factor Stat3, and its phosphorylation is accurately recapitulated in a new nucleophosmin (NPM)-ALK transgenic mouse model of lymphomagenesis. Here we show by gene targeting that Stat3 is required for the transformation of mouse embryonic fibroblasts in vitro, for the development of B-cell lymphoma in transgenic mice and for the growth and survival of both human and mouse NPM-ALK-transformed B and T cells. Ablation of Stat3 expression by antisense oligonucleotides significantly (P < 0.0001) impaired the growth of human and mouse NPM-ALK tumors in vivo. Pharmacological ablation of Stat3 represents a new candidate approach for the treatment of human lymphoma
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PMID:Stat3 is required for ALK-mediated lymphomagenesis and provides a possible therapeutic target. 1593 66

Anaplastic lymphoma kinase (ALK)-positive diffuse large B-cell lymphoma (DLBCL) is a rare, recently defined tumor distinct in many aspects from ALK-positive anaplastic large cell lymphoma (ALCL). We present two additional cases of ALK+DLBCL recently diagnosed in our department and a review of literature. A 48-year old man presented with a large upper neck mass growing slowly over 18 months. Histologically the tumor was diagnosed as an ALK-positive diffuse large B-cell lymphoma. with plasmablastic features. Large, frequently intrasinusoidal tumor cells expressed CD138, EMA, weakly IgA and kappa, but were negative for other B-cell markers, T-cell markers and CD30. The ALK staining was cytoplasmic with the increased intensity in the Golgi area. At the diagnosis the patient manifested with the stage IIIB. Three courses of CHOP resulted in partial and only transient remission. The patient died of massive bleeding from his decomposing tumor 3 months after the diagnosis. A 49-year old man complaining of abdominal pain revealed abdominal lymphadenomegaly and a gastric infiltrate, involving the deep portions of the gastric wall. The tumor showed immunoblastic/anaplastic morphology, with some Reed-Sternberg-like cells positive for ALK. ALK immunostaining was cytoplasmic, weak in a routine immunostain, enhanced with double (proteinase + pressure cooker) antigen retrieval. FISH was consistent with the t(2;5)/nucleophosmin(NPM)-ALK rearrangement. The tumor demonstrated similar "null" B/T phenotype with positivity for IgA, lambda, EMA and LCA. The patient (stage IVB) currently undergoes chemotherapy. ALK-positive DLBCL affects mostly middle-aged men, shows generally poor but stage-dependent prognosis (at least 60% mortality rate), presents typically as a lymph node-based disseminated disease, and very rarely involves the bone marrow. Genetic studies showed that the majority of ALK+DLBCL cases are characterized by the clathrin (CLTC)-ALK fusion and in a few cases the NPM-ALK rearrangement has been found.
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PMID:ALK-positive diffuse large B-cell lymphoma: two more cases and a brief literature review. 1592 Oct 12

Anaplastic large cell lymphoma (ALCL) comprises approximately 25 % of all non-Hodgkin lymphomas in children and young adults. 40% of these tumours have a translocation t(2;5)(p23;q35), which fuses the nucleophosmin gene (NPM) to the anaplastic lymphoma kinase gene (ALK) resulting in a hybrid protein which contributes to the pathogenensis of ALCL. To further analyse the transforming activity in an animal model, a cDNA encoding the protein product, NPM-ALK, was incorporated into a retrovirus construct and introduced into mouse bone marrow progenitors by infection. In a bone marrow gene transfer and transplantation protocol the hematopoietic compartments of lethally irradiated IL-9 transgenic mice were reconstituted with npm-alk infected progenitor cells. IL-9 transgenic mice were chosen, because IL-9, a pleiotropic T helper 2 cytokine, is expressed in most cases of human ALCL and was shown to have an oncogenic potential at least on T cells. Reconstituted mice developed NPM-ALK positive lymphomas including lymphoblastic lymphomas of T-cell type (T-LB), mature and immature plasmacytoma (PZ) and plasmoblastic/anaplastic diffuse large B-cell lymphoma after 10-30 weeks. The combined overexpression of NPM-ALK and IL-9 exerts cooperative oncogenic activity in the transformation of murine lymphoid cells leading to accelerated and enhanced development of T-LB. Many animals developed plasmacytic/plasmoblastic neoplasms, of which the most aggressive tumours share many features with human anaplastic/plasmoblastic diffuse large B-cell lymphoma.
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PMID:[Overexpression of NPM-ALK induces different types of malignant lymphomas in IL-9 transgenic mice]. 1688 16

The proapoptotic B-cell lymphoma-2 family protein Bax is a key regulatory point in the intrinsic apoptotic pathway. However, the factors controlling the process of Bax activation and translocation to mitochondria have yet to be fully identified and characterized. We performed affinity chromatography using peptides corresponding to the mitochondrial-targeting region of Bax, which is normally sequestered within the inactive structure. The molecular chaperone nucleophosmin was identified as a novel Bax-binding protein by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Reciprocal co-immunoprecipitation and proximity assays confirmed the Bax-nucleophosmin protein-protein interaction and verified that nucleophosmin only bound to activated conformationally altered Bax. Confocal microscopy in a cell-based apoptosis model, demonstrated that nucleophosmin translocation from nucleolus to cytosol preceded Bax movement. Specific knockdown of nucleophosmin expression using RNAi attenuated apoptosis as measured by mitochondrial cytochrome c release and activation of the caspase cascade. In a mouse model of ischaemic stroke, subcellular fractionation studies verified that nucleophosmin translocation occurred within 3 h, at a time before Bax translocation but after Bax conformational changes have occurred. Thus, we have elucidated a novel molecular mechanism whereby Bax becomes activated and translocates to the mitochondria to orchestrate mitochondrial dysfunction and apoptotic cell death, which opens new avenues for therapeutic intervention.
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PMID:Nucleophosmin is a novel Bax chaperone that regulates apoptotic cell death. 1707 49

Anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma is a rare subtype of diffuse large B-cell lymphoma (DLBCL). Although a few cases of ALK-positive large B-cell lymphoma harbor nucleophosmin-ALK chromosomal translocation similar to ALK-positive anaplastic large cell lymphoma, most reported cases are characterized by t(2;17)(p23;q23) involving the clathrin gene. Here, we report 2 cases of ALK-positive DLBCL. The 2 cases presented similar morphologic features and immunohistochemical characteristics, that is, positivity for ALK, IgA, CD138, and MUM1; weak positivity for CD30 and CD79a; and negativity for CD20. The clathrin-ALK transcript was identified by reverse transcription-polymerase chain reaction, and the sequence was determined by direct sequencing. Recently, the essential role of STAT3 activation as well as STAT 5 activation in nucleophosmin-ALK fusion protein-mediated lymphomagenesis was reported. However, differential effects of ALK-fusion variant proteins on proliferation, transformation, and invasion properties were reported. Thus, we evaluated the phosphorylation status of STAT 3 and STAT 5, and found highly hyperphosphorylated STAT 3 on tyrosine 705 but not STAT 5 in our 2 cases of ALK-positive DLBCL with clathrin-ALK fusion. Furthermore, STAT 5A expression was not detected in either of the ALK-positive DLBCL cases, although 11 of the 36 ALK-negative DLBCL cases revealed STAT 5A expression. Expression of the antiapoptotic proteins survivin and BCL-X(L), which were believed to be the targets of STAT 3, was investigated. However, there were no significant associations between expression of survivin or BCL-X(L) and ALK positivity among the diffuse large B-cell lymphomas. In summary, similar signaling transduction mechanism involving STAT proteins seems to underlie DLBCL harboring the clathrin-ALK or nucleophosmin-ALK fusion gene.
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PMID:Hyperactivated STAT3 in ALK-positive diffuse large B-cell lymphoma with clathrin-ALK fusion. 1875 94

ALK-positive large B-cell lymphomas usually harbor clathrin (CLTC)-ALK rearrangement or, more rarely, nucleophosmin (NPM)-ALK fusion gene. Here we report a large B-cell lymphoma with a peculiar pattern of diffuse and cytoplasmic immunohistochemical staining and carrying sequestosome 1 (SQSTM1)-ALK rearrangement, identified by reverse transcription polymerase chain reaction analysis and Rapid Amplification of cDNA Ends analysis and confirmed by fluorescence in situ hybridization with specific dual-color fusion probes. The gene fusion product and the transcription factor STAT3 are both phosphorylated, and thereby the pathogenetic mechanism of this case shows important analogies with that of NPM-ALK and CLTC-ALK lymphomas, in which STAT3 plays a central role in the lymphomagenesis. Consequently, STAT3 inhibition provides a possible therapeutic target also for lymphomas with SQSTM1-ALK variant translocation.
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PMID:STAT3 pathway is activated in ALK-positive large B-cell lymphoma carrying SQSTM1-ALK rearrangement and provides a possible therapeutic target. 2358 72


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