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

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.
 ...
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.
 ...
PMID:Deregulated PAX-5 transcription from a translocated IgH promoter in marginal zone lymphoma. 980 80

Although primary mediastinal (thymic) large B-cell lymphoma has been primarily studied, its precise phenotype, molecular characteristics, and histogenesis are still a matter of debate. The International Extranodal Lymphoma Study Group collected 137 such cases for extensive pathological review. Histologically, the lymphomatous growth was predominantly diffuse with fibrosis that induced compartmentalized cell aggregation. It consisted of large cells with varying degrees of nuclear polymorphism and clear to basophilic cytoplasm. On immunohistochemistry, the following phenotype was observed: CD45(+), CD20(+), CD79a(+), PAX5/BSAP(+), BOB.1(+), Oct-2(+), PU.1(+), Bcl-2(+), CD30(+), HLA-DR(+), MAL protein(+/-), Bcl-6(+/-), MUM1/IRF4(+/-), CD10(-/+), CD21(-), CD15(-), CD138(-), CD68(-), and CD3(-). Immunoglobulins were negative both at immunohistochemistry and in situ hybridization. Molecular analysis, performed in 45 cases, showed novel findings. More than half of the cases displayed BCL-6 gene mutations, which usually occurred along with functioning somatic IgV(H) gene mutations and Bcl-6 and/or MUM1/IRF4 expression. The present study supports the concept that a sizable fraction of cases of this lymphoma are from activated germinal center or postgerminal center cells. However, it differs from other aggressive B-cell lymphomas in that it shows defective immunoglobulin production despite the expression of OCT-2, BOB.1, and PU.1 transcription factors and the lack of IgV(H) gene crippling mutations.
 ...
PMID:Primary mediastinal B-cell lymphoma: high frequency of BCL-6 mutations and consistent expression of the transcription factors OCT-2, BOB.1, and PU.1 in the absence of immunoglobulins. 1250 7

We have addressed whether aberrant ongoing hypermutation can be detected in the proto-oncogenes PIM1, c-MYC, RhoH/TTF, PAX5, and the tumor-suppressor gene CD95 in primary central nervous system lymphomas (PCNSLs) derived from immunocompetent HIV-negative patients. Nine of 10 PCNSLs analyzed harbored somatic mutations in the PIM1, c-MYC, RhoH/TTF, and PAX5 genes, but not in the CD95 gene, with 8 tumors carrying alterations in at least 2 of these genes. Furthermore, ongoing aberrant mutation was evidenced in a subset of PCNSLs (2 of 3). Although most of the mutations corresponded to base pair substitutions, deletions were also present. The mean mutation frequency was approximately 60-fold lower for these genes compared with the values obtained for immunoglobulin genes in PCNSL. They were increased 2- to 5-fold compared with extracerebral diffuse large B-cell lymphoma (DLBCL). In summary, our data demonstrate aberrant somatic hypermutations at high frequency in the PIM1, PAX5, RhoH/TTF, and c-MYC genes in most PCNSLs. These findings may indicate a pathogenic role for aberrant somatic hypermutation in PCNSL development. In contrast, although mutations were detected in exon 9 of the CD95 gene, the lack of mutations in the 5' region provides no evidence for the CD95 gene as a target for aberrant somatic mutation.
 ...
PMID:Primary diffuse large B-cell lymphomas of the central nervous system are targeted by aberrant somatic hypermutation. 1459 32

Even with routine immunohistochemical evaluation, distinguishing classic Hodgkin lymphoma (CHL) from diffuse large B-cell lymphoma (DLBCL) or anaplastic large cell lymphoma (ALCL) can be difficult. In these cases, the transcription factors (B cell-specific activator protein [BSAP], octamer-binding transcription factor 2 [Oct-2], and B-cell Oct-binding protein 1 [BOB.1]) and the pan-B-cell markers (CD20, CD22, and CD79a) may aid in clarifying the diagnosis. In 57 cases of CHL, 5 cases of nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), and 33 cases of non-Hodgkin lymphoma (25 DLBCL and 8 ALCL) we found the transcription factor phenotype BSAP+ and either Oct-2- or BOB.1- to be predictive of CHL; BSAP+/Oct-2+/BOB.1+ was predictive of NLPHL or DLBCL, while BSAP- was predictive of ALCL. Expression of all 3 pan-B-cell markers was seen only in NLPHL and DLBCL; positivity for a single B-cell marker was present only in CHL. Thus, together, the transcription factors and pan-B-cell markers might be useful in the differential diagnosis of CHL.
 ...
PMID:The B-cell transcription factors BSAP, Oct-2, and BOB.1 and the pan-B-cell markers CD20, CD22, and CD79a are useful in the differential diagnosis of classic Hodgkin lymphoma. 1460 5

The frequency of Epstein-Barr virus (EBV) in anaplastic large cell lymphoma (ALCL) has been controversial. The interpretation of previous studies is complicated by the use of nonuniform EBV detection methods and the inclusion of cases of CD30-positive diffuse large B-cell lymphoma and so-called "ALCL, Hodgkin-like," as defined in the Revised European-American Lymphoma classification scheme. In the current World Health Organization (WHO) classification system, both of these tumors are excluded from the ALCL category. Also, recently developed antibodies (eg, the antibody specific for PAX-5/B-cell-specific activator protein [BSAP]) provide new, sensitive tools for identifying neoplasms of B-cell lineage that can morphologically resemble ALCL. In this study we evaluated 64 cases of ALCL of T- or null-cell lineage, defined according to the WHO classification system, for the presence of EBV. All tumors were negative for B-cell antigens, including PAX-5/BSAP and CD20 or CD79a. The study group included 27 (42%) anaplastic lymphoma kinase (ALK)-positive (18 T-cell and 9 null-cell) and 37 (58%) ALK-negative (30 T-cell and 7 null-cell) tumors analyzed by in situ hybridization for EBV-encoded RNA (EBER) or immunohistochemistry for EBV-latent membrane protein type 1. All 64 cases were negative for EBV. We conclude, based on the current definition of ALCL in the WHO classification, there is no role for EBV in ALCL arising in Western patients. We suggest that published reports of EBV in a small proportion of ALCL cases in Western patients can be explained by the inclusion of tumors no longer considered to be in the current classification of ALCL, such as CD30-positive anaplastic tumors of B-cell origin.
 ...
PMID:Absence of Epstein-Barr virus in anaplastic large cell lymphoma: a study of 64 cases classified according to World Health Organization criteria. 1511 26

Controversy still exists over the response to therapy and prognosis of patients with primary mediastinal B-cell lymphoma (PMBL). Recent data from the International Extranodal Lymphoma Study Group (IELSG) suggest that a MACOP-B (methotrexate, adriamycin, cyclophosphamide, vincristine, prednisone, bleomycin) chemotherapy regimen followed by radiotherapy may be a better induction strategy than other previously used treatments. Although the pathobiology of PMBL has been widely studied, its precise histology, phenotype, and molecular characteristics are still not clear. To date, phenotypic analysis has revealed the following phenotype: positivity for CD45 and CD20, but negativity for CD3, CD10, CD21, Class I/II major histocompatibility antigens, and a variety of other immunohistochemical markers. CD79a is generally detected, despite an absence of surface immunoglobulins (Igs). CD30 staining is observed in most cases, but is weaker and less homogeneous than in classic Hodgkin's lymphoma or anaplastic large cell lymphoma. BCL-2 protein is usually expressed but there are few data describing the expression of MUM1/IRF4, PAX5/BSAP, BCL-6, or the B-cell transcription factors BOB.1, Oct-2, and PU.1. Cytogenetic studies reveal gains in segments of chromosome 9p, including amplification of the REL proto-oncogene and the tyrosine kinase gene JAK2. Other molecular findings include: C-myc mutations or rearrangements, p53 mutations, IgV(H), gene mutations, and bcl-2 and mal over-expression. bcl-6 mutations and bcl-2 gene rearrangements are generally absent, suggesting that PMBL is of pre-germinal center (GC) origin. However, two recent reports show isotype-switched Ig genes with a high frequency of somatic hypermutations as well as variants in the 5' noncoding region of the bcl-6 gene. The IELSG collected 137 PMBL cases for extensive pathologic review. Histologically, the lymphomatous growth was predominantly diffuse with sclerosis that induced compartmentalized cell aggregation. It consisted of large cells with varying degrees of nuclear polymorphism and clear to basophilic cytoplasm. Molecular analysis was performed on 40 cases and showed novel findings. More than half of the cases displayed bcl-6 gene mutations, which usually occurred together with functioning somatic IgV(H) gene mutations, and BCL-6 and/or MUM1/IRF4 expression. The present study supports the concept that PBML is derived from activated GC or post-germinal center cells. However, it differs from other aggressive B-cell lymphomas in that it shows defective Ig production despite the expression of Oct-2, BOB.1, and PU.1 transcription factors, and a lack of IgV(H) gene crippling mutations.
 ...
PMID:Pathobiology of primary mediastinal B-cell lymphoma. 1520 21

Nodular lymphocyte predominance Hodgkin's disease (NLPHD), previously called nodular paragranuloma, is a rare entity recognized as a clinico-pathological entity distinct from classic Hodgkin's lymphoma. It is an indolent B cell lymphoma derived from a germinal center cell. NLPHD may closely resemble lymphocyte-rich classic Hodgkin's disease (LR-CHD) or T-cell or histiocyte-rich large B-cell lymphoma (TCRLBCL). A reproducible distinction between these entities is difficult but the classification is prognostically relevant. NLPHD is characterized by neoplastic "popcorn" cells CD20+ CD30- CD15- EMA+ Bcl6+ scattered within a nodular background predominantly composed of small B lymphocytes. LR-CHD neoplastic proliferation is composed of CD20+/- CD30+ CD15+/- EMA- Bcl6+/- Reed Sternberg or Hodgkin's cells, scattered within numerous CD3+ T cells. TCRLBCL is an agressive lymphoma composed of CD20+ CD30- CD15- EMA+/- Bcl6+/- polymorphic neoplastic cells, scattered within a mixture of CD3+ T cells and histiocytes. Epstein Barr virus is detectable within half cases of LR-CHD, but never in NLPHD and rarely in TCRLBCL. The transcription factors BOB1, PU-1, BSAP and IRF4 are new markers that could be useful for differential diagnosis.
 ...
PMID:[Nodular lymphocyte predominance Hodgkin's disease and its differential diagnosis]. 1522 Aug 30

Immunoproliferative small intestinal disease (IPSID) was recently added to the growing list of infectious pathogen-associated human lymphomas. Molecular and immunohistochemical studies demonstrated an association with Campylobacter jejuni. IPSID is a variant of the B-cell lymphoma of mucosa-associated lymphoid tissue (MALT), which involves mainly the proximal small intestine resulting in malabsorption, diarrhea, and abdominal pain. Geographically, IPSID is most prevalent in the Middle East and Africa. IPSID lymphomas reveal excessive plasma cell differentiation and produce truncated alpha heavy chain proteins lacking the light chains as well as the first constant domain. The corresponding mRNA lacks the variable heavy chain (V(H)) and the constant heavy chain 1 (C(H)1) sequences and contains deletions as well as insertions of unknown origin. The encoding gene sequence reveals a deletion of V region and parts of C(H)1 domain. Cytogenetic studies demonstrated clonal rearrangements involving predominantly the heavy and light chain genes, including t(9;14) translocation involving the PAX5 gene. Early-stage IPSID responds to antibiotics (30%-70% complete remission). Most untreated IPSID patients progress to lymphoplasmacytic and immunoblastic lymphoma invading the intestinal wall and mesenteric lymph nodes, and may metastasize to a distant organ. IPSID lymphoma shares clinical, morphologic, and molecular features with MALT lymphoma, lymphoplasmacytic lymphoma, and plasma cell neoplasms.
 ...
PMID:Immunoproliferative small intestinal disease (IPSID): a model for mature B-cell neoplasms. 1554 84

We present an extensive characterization of 10 B-cell lymphomas with a t(9;14)(p13;q32). The presence of the PAX5/IGH gene rearrangement was demonstrated by fluorescence in situ hybridization (FISH) using a validated probe set, whereas complex karyotypic changes were reassessed by multiplex-FISH (M-FISH). Pathologic and clinical review revealed the presence of this rearrangement in 4 histiocyte-rich, T-cell-rich B-cell lymphomas (HRTR-BCLs) and 2 posttransplantation diffuse large B-cell lymphomas (PTLD-DLBCLs). In contrast to initial observations describing this translocation in lymphoplasmacytic lymphoma (LPL) and LPL-derived large B-cell lymphoma, our data showed a wide morphologic and clinical spectrum associated with the PAX5/IGH rearrangement, pointing to an association between this aberration and a subset of de novo DLBCLs presenting with advanced disease and adverse prognosis. In addition, the recurrent incidence of this rearrangement in both HRTR-BCL (4 cases) and PTLD-DLBCL (2 cases) was previously unrecognized and is intriguing.
 ...
PMID:PAX5/IGH rearrangement is a recurrent finding in a subset of aggressive B-NHL with complex chromosomal rearrangements. 1594 42


1 2 3 4 5 6 7 8 9 Next >>