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)

p63, a member of the p53 family, is involved in the survival and differentiation of reserve/stem cells in different epithelia. To unveil the possible role of p63 in thymic physiology and pathology, we investigated the expression of p63 isoforms in normal thymus, thymomas and other mediastinal tumours. All samples were analysed using immunohistochemistry with three different antibodies: 4A4 antibody recognising all p63 isoforms, p40 antibody reacting only with truncated dominant-negative isoforms (DeltaN-p63) and H-129 antibody recognising all alpha-isoforms. Reverse-transcription polymerase chain reaction (RT-PCR), and real-time PCR analyses were performed on RNA extracted from frozen samples of four thymomas and two primary-mediastinal large-B-cell lymphoma (PMLBCL). In normal thymus, DeltaN-p63alpha was expressed in all cortical and medullary epithelial cells, with decreasing intensity in Hassall's corpuscles. This phenotype was conserved in neoplastic transformation since all 54 investigated thymomas (World Health Organization types A, AB, B1, B2, B3, C) expressed DeltaN-p63alpha (virtually 100% cells). The predominance of DeltaN-p63alpha isoform mRNA was confirmed by real-time PCR. Among other mediastinal tumours, DeltaN-p63alpha was only expressed in those displaying either a stratified epithelial component (teratomas) or epidermoid differentiation (lung carcinoma). Among lymphomas, T-cell-precursor lymphomas did not express p63, whereas most PMLBCL expressed TA-p63alpha (7/8).
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PMID:Constitutive expression of DeltaN-p63alpha isoform in human thymus and thymic epithelial tumours. 1285 17

Arsenicalism has been observed throughout the world and has become an urgent public health concern. The authors explored the mechanism of carcinogenesis of inorganic arsenic in patients with arsenicalism from coal-burning pollution. The 68 subjects were divided into 3 groups--carcinoma, precarcinoma, and common-on the basis of pathological diagnosis. The expressions of proliferating cell nuclear antigen (PCNA), mutant-type P53, and B-cell lymphoma/leukemia-2 (BCL-2) proteins were detected by immunohistochemical staining. PCNA, P53, and BCL-2 proteins were overexpressed. The proteins' overexpressions correlated with the pathological changes seen in each pathological study group (i.e., common < precarcinoma < carcinoma). Statistical correlation was observed between P53 and BCL-2, and between PCNA and BCL-2. The authors concluded that cell proliferation, antiapoptosis, and up-regulation of the mutant-type P53 gene played vital roles in the pathological development of arsenicalism.
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PMID:Molecular pathology of skin carcinogenesis due to arsenicalism from coal-burning. 1289 9

Some follicular lymphomas histologically transform into diffuse aggressive lymphomas, the prognosis of which is poor. There are, however, no reliable histological criteria for predicting which cases will later undergo such transformation. In low-grade B-cell lymphomas, follicular dendritic cells form dense mesh-like networks that contain accumulating neoplastic B-cells. These are rare in high-grade lymphomas. We immunohistochemically analyzed CD21-positive follicular dendritic cells in 32 follicular lymphomas, including 3 transformed lymphomas, in addition to immunohistological study using P-glycoprotein, p53, and Ki-67. We found that the mesh-like networks in follicles are more clearly defined in low-grade lymphomas than in high-grade lymphomas (p = 0.015). Neoplastic follicles in 2 transformed lymphomas lost the networks of follicular dendritic cells before transformation despite the existence of morphologically clear follicles. This differed from the non-transformed cases of the same cytological grades. Prognosis was statistically better for patients with low-grade tumor than for those with high-grade tumor (p = 0.026), and there was a trend toward poorer survival among CD21-negative cases (p = 0.186). P-glycoprotein, p53, and Ki-67 expressions did not provide sufficient information to predict the transformation of follicular lymphoma. The presence of CD21-positive follicular dendritic cells in neoplastic follicles might help predict the potential of follicular lymphoma to transform to diffuse large B-cell lymphoma.
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PMID:Disappearance of CD21-positive follicular dendritic cells preceding the transformation of follicular lymphoma: immunohistological study of the transformation using CD21, p53, Ki-67, and P-glycoprotein. 1290 19

To identify molecular features of neoplasms associated with EB virus, human peripheral blood lymphocytes (huPBL) were isolated from healthy volunteer donors and were transplanted intraperitoneally into SCID mice, and then huPBL/SCID mice were infected with EB virus. Serum levels of human IgG were measured by unidirectional immunodiffusion assay. Human Alu sequence and EBER-1 in tumor tissues were detected with PCR and in situ hybridization. Immunohistochemical staining was used to examine leukocyte differentiation antigens (LCA, L26, UCHL1, PS1), viral gene products (LMP1, EBNA2, BZLF1) and cellular oncoproteins (p53, C-myc, Bcl-2 and Bax). The experiments showed that tumors developed in 24 of 34 surviving huPBL/SCID mice by EBV infection. Histopathological and immunohistochemical observations demonstrated that all of the induced tumors in SCID mice were malignant lymphomas derived from human B-lymphocytes. In situ hybridization showed that tumor cells had EBV-encoded small RNA-1 (i.e. EBER-1). Alu sequence could be amplified by PCR from human genome of tumor tissues. Immunohistochemistry detected positive staining of BZLF1-encoded protein in a small population of tumor cells of almost all cases, and positive staining of LMP1 and EBNA2 only in small number of tumor cells. Human IgG could be found in the serum of 12 SCID mice on the 15th day after huPBL engraftment, and then increased with time and with the development of induced tumors in 6 mice. Positive rates of p53, C-myc, Bcl-2 and Bax expression were 83.33%, 100%, 95.83%, 91.67%, respectively, in 24 cases of the EBV-induced lymphomas. The results indicate that molecular lesions associated with the induced B-cell lymphoma involved EBV infection, expression of oncogenic viral genes, and abnormal expression of cellular oncogenes in human xenografts. Human IgG level in the serum of huPBL/SCID mice can be considered as a useful index for tumor development.
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PMID:[Molecular pathological characteristics of human B-cell lymphomas induced by Epstein-Barr virus]. 1451 11

We have previously shown a critical role for IFN regulatory factor 5 (IRF-5) in the innate immune response to virus infection. For the first time, we now show that although IRF-5 is a direct target of p53, its cell cycle regulatory and proapoptotic effects are p53 independent. IRF-5 inhibits both in vitro and in vivo B-cell lymphoma tumor growth in the absence of wild-type p53. The molecular mechanism(s) of IRF-5-mediated growth inhibition is associated with a G(2)-M cell cycle arrest and modulation of growth regulatory and proapoptotic genes, including p21, Bak, DAP kinase 2, and Bax. Taken together, these data indicate that although IRF-5 is a downstream target of p53, its growth inhibitory and proapoptotic effects are independent of p53.
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PMID:Interferon regulatory factor 5, a novel mediator of cell cycle arrest and cell death. 1455 32

The histological transformation from a follicular lymphoma (FL) to a diffuse large B-cell lymphoma (DLBL) occurs in 22% to 30% of all cases of FL. The aim of this study was to identify specific chromosomal gains/losses associated with transformation of FL to DLBL, in addition to the well-known mechanisms like p53 mutation and protein expression and c-myc translocation and up-regulation. This is the first study to meet 2 important conditions for such a comparison. First, we demonstrate that the FL and the DLBL were clonally related, based on identical immunoglobulin gene rearrangements in 5 of the 6 cases. Second, we used laser microdissection microscopy to isolate only the neoplastic cells from the initial FL samples. The results indicate that no single chromosomal abnormality seems to be responsible for the transformation of FL to DLBL. P53 protein overexpression was found in 4 and c-myc translocation in 3 of the 6 transformed DLBLs, but not in the initial FL samples. Additional chromosomal abnormalities were detected by comparative genomic hybridization in all 6 cases when the DLBL was compared with the FL. In the 5 cases with transformation of grade 1 or 2 FL to DLBL, gains at chromosomes 7 (5 of 5 cases), 10p1 (3 of 5 cases), 12 (3 of 5 cases), and 20p13 (2 of 5 cases) and loss at 9q (4 of 5 cases) were the most frequently found abnormalities. A gain on chromosome 7p, in combination with a loss on 9q, was found in 4 of the 5 DLBL that transformed from FL grade 1 or 2.
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PMID:Identification of chromosomal copy number changes associated with transformation of follicular lymphoma to diffuse large B-cell lymphoma. 1456 88

B-cell lymphoma gene (BCL-6) upregulation contributes to immortalization of mouse embryo fibroblast and primary B cells via upregulation of cyclin D1. As cyclin D1 overexpression is a common phenomenon in different cancers, BCL-6 protein overexpression may not be restricted to lymphomas. In this study, expression of BCL-6 was investigated by immunohistochemistry on paraffin-embedded specimens from 150 breast cancer patients and 10 specimens of normal breast tissue. The results showed BCL-6 overexpression (> or =10% of cells) in 24/150 (16%) breast cancer patients, whereas in normal breast low expression (<1%) of BCL-6 was observed. In linear regression analysis BCL-6 expression was associated with cyclin D1 (r=0.197, P=0.016). Further, in chi2 analyses, BCL-6-positivity was associated with overexpression of p53 (P=0.016), and hypoxia-inducible factor-1alpha (P<0.001). Involvement of BCL-6 in breast carcinogenesis is further underscored by comparative genomic hybridization analysis that showed gains at the BCL-6 locus (3q27) in 14/86 (16%) breast cancer tissues. The cases with amplification in BCL-6 showed an increased (25%) incidence of BCL-6 protein overexpression. Thus, this study is the first to show that BCL-6 oncogene activation plays a role in cancers other than lymphomas.
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PMID:Protein expression of B-cell lymphoma gene 6 (BCL-6) in invasive breast cancer is associated with cyclin D1 and hypoxia-inducible factor-1alpha (HIF-1alpha). 1465 91

Chromosomal rearrangements in non-Hodgkin's B-cell lymphoma implicate BCL-6 as an oncogene, yet direct evidence for BCL-6 acting as an oncogene in B cells has been lacking. Here, we show that BCL-6 can immortalize primary B cells, but only in the absence of p53 tumor suppressor function. The expression of BCL-6 led to greatly increased B-cell proliferation, particularly in response to CD40 stimulation. Furthermore, BCL-6-infected p53-deficient B cells gave rise to immortalized cell lines that could be maintained by CD40 stimulation. We found that in primary mouse B cells, BCL-6 repressed expression of the Blimp-1, p27kip1, and cyclin D2 target genes. BCL-6 did not markedly repress the PDCD2 and BCL-XL target genes. The BCL-6 immortalized cell lines had a phenotype consistent with germinal center B cells, they expressed the germinal center-specific M17 gene, and a significant fraction of the cells stained positive with PNA. Our data indicate that BCL-6 may act to maintain B cells in a germinal center-like state, and repression of Blimp-1 by BCL-6 may be particularly crucial for stabilization of the germinal center phenotype. Our data also suggest that disruption of the p53 pathway may be crucial for the development of BCL-6-expressing B-cell lymphomas.
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PMID:Transcriptional repressor BCL-6 immortalizes germinal center-like B cells in the absence of p53 function. 1473 19

Cdc25B and cdc25A phosphatases are representative stimulators of cell cycle progression, and recent studies have also indicated their oncogenic roles. In this study, we investigated the expression of these phosphatases in malignant lymphoma of the thyroid by immunohistochemistry. These phosphatases were not expressed in follicular cells in normal follicles, but were heterogeneously or diffusely expressed in the follicles in chronic thyroiditis and malignant lymphoma. In infiltrating lymphocytes in chronic thyroiditis, they were only occasionally expressed. Of the 47 cases of lymphoma, 30 (63.8%) were classified as high group for cdc25B because it was expressed in more than 25% of lymphoma cells. Cdc25B expression level was inversely associated with MIB-1 labeling index (p=0.0008), and aberrant p53 expression (p=0.0077). Furthermore, cases of marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MZBL) were more frequently classified as high group (p=0.0318) than those of diffuse large B-cell lymphoma (DLBL). On the other hand, 22 cases (46.8%) were regarded as high group for cdc25A, but its expression level was not linked to those parameters. These findings suggest that i) cdc25B plays a role in the early phase of thyroid lymphoma possibly including the malignant transformation from chronic thyroiditis, and ii) cdc25A may contribute to the progression of lymphoma.
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PMID:Cdc25A and cdc25B expression in malignant lymphoma of the thyroid: correlation with histological subtypes and cell proliferation. 1476 75

Hepatitis C virus (HCV) is a nonretroviral oncogenic RNA virus, which is frequently associated with hepatocellular carcinoma (HCC) and B cell lymphoma. We demonstrated here that acute and chronic HCV infection caused a 5- to 10-fold increase in mutation frequency in Ig heavy chain, BCL-6, p53, and beta-catenin genes of in vitro HCV-infected B cell lines and HCV-associated peripheral blood mononuclear cells, lymphomas, and HCCs. The nucleotide-substitution pattern of p53 and beta-catenin was different from that of Ig heavy chain in HCV-infected cells, suggesting two different mechanisms of mutation. In addition, the mutated protooncogenes were amplified in HCV-associated lymphomas and HCCs, but not in lymphomas of nonviral origin or HBV-associated HCC. HCV induced error-prone DNA polymerase zeta, polymerase iota, and activation-induced cytidine deaminase, which together, contributed to the enhancement of mutation frequency, as demonstrated by the RNA interference experiments. These results indicate that HCV induces a mutator phenotype and may transform cells by a hit-and-run mechanism. This finding provides a mechanism of oncogenesis for an RNA virus.
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PMID:Hepatitis C virus induces a mutator phenotype: enhanced mutations of immunoglobulin and protooncogenes. 1499 97


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