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Query: UMLS:C0079731 (B-cell lymphoma)
 16,671 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously demonstrated that the breakpoint of t(11;14)(q23;q32) in the RC-K8 B cell lymphoma cell line lies between CD3 and THY1/ETS1 on chromosome 11q23, and we cloned this region and named it the rck locus. Pulsed-field gel electrophoresis showed that the rck probe B (distal to the breakpoint) and the porphobilinogen deaminase (PBGD) probe detect the same germ line band and also the same rearranged band when DNA from RC-K8 cells was digested with NotI enzyme. Furthermore, Southern blot analysis with somatic cell hybrids showed that the PBGD gene moved to the 14q+chromosome, which confirmed PBGD to be more distal to the centromere than the rck locus. These data allowed us to construct the following order of genes: 11 cen-q23-CD3-rck-PBGD-THY1/ETS1. In this study, three infantile leukemia cell lines with t(11;19)(q23;p13) translocation were also analyzed by pulsed-field gel electrophoresis. CD3D probe detected the rearranged bands in DNA from two of them after digestion with NotI and SacII enzymes, demonstrating that the breakpoints of both cell lines were estimated to be within 360 kilobases of CD3D.
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PMID:Rearrangements on chromosome 11q23 in hematopoietic tumor-associated t(11;14) and t(11;19) translocations. 174 46

Clinical, histologic, cytogenetic, and molecular genetic data of 31 patients with extranodal, nodal, and splenic marginal zone B-cell lymphoma (MZBCL) are presented. Despite these variable clinical manifestations, a similar spectrum of morphologic features as well as distinctive immunophenotypic findings were noted. In all cases, a monotypic B-cell proliferation consistently negative for CD5, CD10, and CD23 was found expanding the marginal zone of the B follicle with and without colonization of the follicle centers. Clonal chromosomal abnormalities were detected in 23 of the 31 patients. Recurrent aberrations included whole or partial trisomy 3 (18 cases), trisomy 18 (9 cases), and structural rearrangements of chromosome 1 with breakpoints in 1q21 (9 cases) or 1p34 (6 cases), all of which were seen in extranodal, nodal, as well as splenic MZBCL. Abnormalities of the additional chromosome 3, such as +del(3)(p13),+i(3)(q10), or structural changes involving the distal part of the long arm, were evident in 9 of the 18 cases. All recurrent abnormalities were found in MZBCL more frequently than in other histologic entities of B-cell non-Hodgkin's lymphoma (B-NHL). None of the known lymphoma-associated chromosomal changes or rearrangements of the BCL1, BCL2, BCL3, BCL6, and CMYC genes were detected. We conclude that MZBCL represent a distinct entity of B-NHL with characteristic morphologic and immunophenotypic features and particular chromosomal abnormalities, and that a close histogenetic relationship between extranodal, nodal, and splenic MZBCL is likely, although the clinical presentation may vary.
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PMID:Marginal zone B-cell lymphomas of different sites share similar cytogenetic and morphologic features. 869 24

Trisomy 3 represents the most frequent and consistent chromosomal abnormality characterizing the recently defined entity marginal zone B-cell lymphoma (MZBCL). By cytogenetic analysis and/or fluorescence in situ hybridization (FISH) on interphase nuclei we found in increased copy number of chromosome 3 in 22/36 (61%) successfully analysed cases, including 8/12 cases with extranodal MZBCL, 8/13 cases with nodal MZBCL, and 6/11 patients with splenic MZBCL. Sensitivity of interphase cytogenetics was somewhat higher than that of conventional cytogenetic investigation. Structural chromosomal changes involving at least one chromosome 3 were seen in 11/20 cases with an increased copy number of chromosome 3: +de(3)(p13) was demonstrated in three cases, and was the sole chromosomal abnormality in one of them; +i(3)(q10) was seen in two other patients; and rearrangements involving various breakpoints on the long arm of chromosome 3 were found in the remaining cases. FISH on metaphase spreads confirmed these structural abnormalities and additionally showed two unexpected translocations involving chromosome 3. We conclude that: (1) trisomy 3 occurs in a high proportion of extranodal, nodal and splenic MZBCL; (2) FISH on interphase nuclei is an additional and sensitive tool in detecting an increased copy number of chromosome 3 in MZBCL; (3) additional structural abnormalities involving the long arm of chromosome 3 are frequent but non-recurrent and are perhaps secondary changes; and (4) abnormalities such as +del(3)(pl3) and +i(3)(q10) suggest that genes located on the long arm of chromosome 3 are of particular importance in the pathogenesis of MZBCL.
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PMID:Trisomy 3 in marginal zone B-cell lymphoma: a study based on cytogenetic analysis and fluorescence in situ hybridization. 861 68

The translocation t(1;19)(q23;p13) is found in 3-5% of all acute lymphoblastic leukaemias (ALL) and results in the expression of an E2A/PBX1 hybrid gene transcript. This translocation is very closely associated with a pre-B phenotype. t(14;18) is associated with follicular B-cell lymphoma and is characterized by over-expression of the bcl-2 oncogene. We describe a case of ALL in an adult with a mature B-cell immunophenotype and a single abnormal cell line with a complex karyotype showing both t(1;19) and t(14;18). Two reports of this phenomenon have been published previously and molecular analysis, where performed, showed the E2A gene was not rearranged, suggesting the t(1;19) was a molecular variant of the established translocation. In contrast, molecular analysis of our case demonstrated expression of the E2A/PBX1 fusion transcript typically associated with t(1;19) in pre-B ALL but showed it to be present at an extremely low level, despite the abnormal karyotype being found in the majority of metaphase cells. Analysis of bcl-2 expression showed a significant up-regulation. A down-regulation of the E2A/PBX1 hybrid gene as a consequence of the enhanced expression of bcl-2 may be a possible mechanism for this finding.
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PMID:A case of mature B-cell ALL with coexistence of t(1;19) and t(14;18) and expression of the E2A/PBX1 fusion gene. 875 23

t(9;14)(p13;q32), a subtype of 14q32 translocation, plays an essential role in the development of lymphoplasmacytoid lymphoma. t(9;14)(p13;q32) Causes juxtaposition of the PAX-5 gene on 9p13 and the IgH gene on 14q32, leading to the deregulation of the PAX-5 gene. We report a case of primary splenic lymphoma with a t(9;14). The histological diagnosis was diffuse large B-cell lymphoma without plasmacytoid differentiation. The lymphoma cells showed a complex karyotype including a t(9;14). Southern blot analysis localized the breakpoint of the PAX-5 gene within a couple of kb regions upstream of the exon 1A, although the involvement of the PAX-5 gene with the immunoglobulin heavy chain gene could not be confirmed.
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PMID:A case of primary splenic large cell lymphoma with a t(9;14)(p13;q32). 963 87

The PAX5 gene encodes the BSAP (B-cell-specific activator protein) which is a key regulator of B-cell development and differentiation. A recurring translocation t(9;14)(p13;q32) in non-Hodgkin's lymphoma moves the PAX5 on 9p13 within close proximity of the immunoglobulin heavy chain gene (IGH). KIS-1 cell line was established from a patient with diffuse large cell lymphoma of B-cell type carrying t(9;14). We analysed PAX5/BSAP expression by Northern and Western blotting in a panel of haematological tumour cell lines with other chromosome abnormalities in comparison with that of KIS-1. PAX5 mRNA and BSAP expression were detected in all B-cell lines tested, and the high level in KIS-1 was confirmed. However, a diffuse large B-cell lymphoma cell line and an acute B-lymphoid/myeloid leukaemia cell line expressed the PAX5/BSAP at levels comparable with KIS-1. PAX5 transcripts were readily detectable in clinical materials with a wide variety of B-cell neoplasms by reverse transcriptase-mediated polymerase chain reaction (PCR). Thus, PAX5/BSAP activation in haematological tumour cells is not necessarily associated with t(9;14). Although binding sites for BSAP have been identified in the promoters of CD19, this study failed to find clear correlation between the level of PAX5/BSAP expression and that of CD19. In contrast to KIS-1 in which the E mu enhancer of IGH was juxtaposed to PAX5, cloning of t(9; 14) from another case by long-distance PCR revealed that the PAX5 promoter was linked to a Cgamma constant region in divergent orientation, suggesting that the mechanism of PAX5 activation through recombination with IGH varies among individual cases. Breakpoints on 9p13 of the two translocations were clustered upstream of PAX5, leaving the PAX5 coding region intact.
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PMID:Expression of the PAX5/BSAP transcription factor in haematological tumour cells and further molecular characterization of the t(9;14)(p13;q32) translocation in B-cell non-Hodgkin's lymphoma. 972 95

The PAX-5 gene codes for the transcription factor BSAP, which is expressed throughout B-cell development. Although loss-of-function mutation in the mouse showed an essential role for Pax-5 in early B lymphopoiesis, gain-of-function mutations have implicated the human PAX-5 gene in the control of late B-cell differentiation. PAX-5 (on 9p13) has been involved together with the immunoglobulin heavy-chain (IgH) gene (on 14q32) in the recurring t(9;14)(p13;q32) translocation that is characteristic of small lymphocytic lymphoma with plasmacytoid differentiation. Here we have characterized a complex t(2;9;14)(p12;p13;q32) translocation present in a closely related non-Hodgkin's lymphoma referred to as splenic marginal zone lymphoma (MZL). In this MZL-1 translocation, the two promoters of PAX-5 were replaced on the derivative chromosome 14 by an immunoglobulin switch Smicro promoter that was linked to the structural PAX-5 gene upstream of its translation initiation codon in exon 1B. Expression analyses confirmed that PAX-5 transcription was upregulated due to efficient initiation at the Smicro promoter in the malignant B lymphocytes of patient MZL-1. For comparison we have analyzed PAX-5 expression in another B-cell lymphoma, KIS-1, indicating that transcription from the distal PAX-5 promoter was increased in this tumor in agreement with the previously characterized translocation of the immunoglobulin Emicro; enhancer adjacent to PAX-5 exon 1A. In both lymphomas, the J-chain gene, which is thought to be under negative control by BSAP, was not expressed, whereas transcription of the putative target gene p53 was unaffected by PAX-5 overexpression. Together these data indicate that the t(9;14)(p13;q32) translocation contributes to lymphoma formation as a regulatory mutation that leads to increased PAX-5 expression in late B-cell differentiation due to promoter replacement or enhancer insertion.
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PMID:Deregulated PAX-5 transcription from a translocated IgH promoter in marginal zone lymphoma. 980 80

The LAZ3(BCL6) gene on chromosome band 3q27 is nonrandomly disrupted in B-cell non-Hodgkin lymphoma (B-NHL) by chromosomal translocations clustered within a 3.3-kb MTC (major translocation cluster) located between the two first noncoding exons. These translocations generally result in the expression of a chimeric mRNA transcript between the LAZ3 gene and sequences derived from the partner chromosome. Using RACE RT-PCR, we previously demonstrated fusion of LAZ3 with the RhoH/TTF gene, a hemopoietic cell-specific small GTPase involved in cytoskeleton organization, and with the BOB1/OBF1 gene, a B-cell-specific coactivator of octamer-binding transcription factors, following translocations t(3;4)(q27;p13) and t(3;11)(q27;q23), respectively. Here we report the identification of the L-Plastin(LCP1) gene as a novel LAZ3 partner in chimeric transcripts resulting from a t(3;13)(q27;q14) translocation, in two cases of B-cell lymphoma. As a consequence of the translocation, the 5' regulatory region of each gene was exchanged, creating both LCP1-LAZ3 and reciprocal LAZ3-LCP1 fusion transcripts in one case, and only a LCP1-LAZ3 fusion transcript in the other. The 13q14 chromosome region is frequently disrupted in various proliferative disorders, and the LCP1 gene defines a new breakpoint site in this region. This gene encodes an actin-binding protein and is the second LAZ3 partner gene, with the RhoH/TTF gene, involved in actin cytoskeleton organization. Genes Chromosomes Cancer 26:97-105, 1999.
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PMID:Nonrandom fusion of L-plastin(LCP1) and LAZ3(BCL6) genes by t(3;13)(q27;q14) chromosome translocation in two cases of B-cell non-Hodgkin lymphoma. 1046 47

The majority of non-Hodgkin lymphomas of B-cell type (B-NHL) exhibit chromosomal abnormalities including many types of reciprocal translocations closely related to specific histopathologic entities. The t(9;14)(p13;q32) has been recognized as a primary genetic event directly involved in the development of lymphoplasmacytic lymphoma. In the 14 published cases, the t(9;14)(p13;32) seems to delineate a variety of low-grade B-cell disorders characterized by a common clinical history and immunopathologic similarities. We report here three new cases presenting a t(9;14)(p13;q32) with other chromosomal abnormalities which have been referred to as B-cell low-grade or high-grade malignant lymphoproliferative disorders. Two of these cases showed diffuse large B cell lymphoma morphology and two patients had a favorable clinical outcome. These data suggest that t(9;14)(p13;q32) is not restricted to low-grade lymphoma.
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PMID:Three new cases of non-Hodgkin lymphoma with t(9;14)(p13;q32). 1288 65

Ectopic expression of fibroblast growth factor receptor 3 (FGFR3) associated with t(4;14) has been implicated in the pathogenesis of human multiple myeloma. Some t(4;14) patients have activating mutations of FGFR3, of which a minority are K650E (thanatophoric dysplasia type II [TDII]). To investigate the role of autophosphorylated tyrosine residues in FGFR3 signal transduction and transformation, we characterized a series of FGFR3 TDII mutants with single or multiple Y-->F substitutions. Phenylalanine substitution of Y760, essential for phospholipase Cgamma (PLCgamma) binding and activation, significantly attenuated FGFR3 TDII-mediated PLCgamma activation, as well as transformation in Ba/F3 cells and a murine bone marrow transplant leukemia model. In contrast, single substitution of Y577, Y724, or Y770 had minimal to moderate effects on TDII-dependent transformation. Substitution of all 4 non-activation loop tyrosine residues significantly attenuated, but did not abolish, TDII transforming activity. Similar observations were obtained in the context of a constitutively activated fusion TEL-FGFR3 associated with t(4;12)(p16;p13) peripheral T-cell lymphomas. Moreover, 2 independent EmuSR-FGFR3 TDII transgenic mouse lines developed a pro-B-cell lymphoma, and PLCgamma was highly activated in primary lymphoma cells as assessed by tyrosine phosphorylation. These data indicate that engagement of multiple signaling pathways, including PLCgamma-dependent and PLCgamma-independent pathways, is required for full hematopoietic transformation by constitutively activated FGFR3 mutants.
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PMID:Constitutively activated FGFR3 mutants signal through PLCgamma-dependent and -independent pathways for hematopoietic transformation. 1578 30


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