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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The polymerase chain reaction (PCR) offers a practical means of studying the molecular genetic features of lymphomas. The method is rapid and, as formalin-fixed, paraffin processed samples can be used, does not require special tissue handling procedures. PCR amplified immunoglobulin and T cell receptor gene rearrangements can be exploited as markers of clonality and lineage and genetic abnormalities such as chromosome translocations and mutations of oncogenes and tumour suppressor genes can be used to identify specific lymphoma types. Polymorphic X linked loci may also be used as markers of clonality in females. Direct sequencing of PCR amplified IGH variable regions has provided insights into the developmental stages, susceptibility to antigen drive and dissemination patterns of lymphomas. The role of oncogenes and tumour suppressor genes such as MYC and TP53 in lymphomas can be studied by PCR amplification of mutation hotspots and direct sequencing of products. Known viral and bacterial DNA can readily be identified using PCR and unknown organisms sought using conserved primers to amplify polymorphic sequences. PCR analysis of the lymphomas and related disorders has accelerated our understanding of their molecular biology and provides a practical tool with diagnostic and prognostic applications. Future development of in situ PCR methods will provide cellular localization of genetic defects and infectious agents.
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PMID:Polymerase chain reaction in the assessment of lymphomas. 954 84

We describe a case of leukemic mantle cell lymphoma (MCL) with complex karyotype and amplification of the CCND1/IGH fusion gene. Testing for the presence of t(11;14), the hallmark of MCL, revealed multiple copies of the fusion signals. We therefore conducted extensive molecular cytogenetic studies to delineate the nature and consequences of such an abnormality. We localized the amplification to the der(14)t(11;14) and to a der(2) chromosome in a form of interspersed chromosome 11 and 14 material. This resulted in high expression of cyclin D1 mRNA and the protein expressed independently of the cell cycle phase. CGH analysis revealed that the overrepresentation on chromosome 11 included chromosomal band 11q23 in addition to the CCND1 locus at 11q13. The band 11q23 harbors the ataxia telangiectasia mutated (ATM) gene recently proposed to be involved in the pathogenesis of MCL with high incidence of deletions in this locus. Using YAC 801e11, containing the ATM gene, we demonstrated several hybridization signals, suggesting that this region also formed part of the amplicon. This case also showed TP53 gene abnormalities: protein expression, monoallelic deletion, and a mutation in exon 5. The clinical course was aggressive, and the patient died within 6 months of presentation. This is to our knowledge the first description of amplification of the CCND1/IGH fusion gene in a human neoplasm, which may have played a role in the fulminating course of the disease in this patient.
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PMID:Unusual case of leukemic mantle cell lymphoma with amplified CCND1/IGH fusion gene. 1179 47

Diffuse large B-cell lymphoma (DLBCL), the most common subtype of adult non-Hodgkin lymphoma (NHL), is infrequently seen in adolescents and is rare in children. Due to the infrequency of the disease, single institution-based cytogenetic and fluorescence in situ hybridization (FISH) studies of pediatric DLBCL have not been reported so far and, hence, the possible differences in pediatric and adult DLBCL have not been evaluated. We performed cytogenetic and FISH analyses of 7 pediatric and 5 young adult DLBCL cases referred to the University of Nebraska Medical Center. Karyotypic studies revealed numeric and structural chromosome abnormalities in all cases. Loss of chromosomes 2, 3, 4, 6, 12, 15, 16, and 17, and gain of 12, 18, and X were observed in more than 20% of the cases (#10878;3 cases). Sex chromosome abnormalities and cytogenetically unidentifiable chromosomes and/or segments were observed in 80% (10/12) of the cases. Recurrent breakpoints (observed in 3 or more cases) included 14q32 (IGH) and 17p13 (TP53), which clustered in the young adult group. The breakpoints 7q36, 9p24, 13q34, and 16q24 were noted in two cases each. We performed interphase FISH studies to verify the possible rearrangements of the breakpoints that are frequently implicated in adult DLBCL. Our results confirmed that the pediatric cases did not show rearrangements of 3q27 (BCL6), 14q32 (IGH), 18q21 (BCL2), 8q24 (CMYC), and 17p13 (TP53), except for one case with IGH;BCL2 dual fusion [t(14;18)(q32;q21)] and one with a 17p13 (TP53) deletion. Although 3q27 was noted to be rearranged by conventional cytogenetics in two young adult DLBCL cases, FISH investigations verified that BCL6 was not disrupted. The t(8;14)(q24;q32) with rearranged CMYC ascertained by FISH, was observed in a single young adult DLBCL case. These results highlight a distinctly different representation of cytogenetic abnormalities in pediatric versus adult DLBCL.
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PMID:Cytogenetics and fluorescence in situ hybridization studies of diffuse large B-cell lymphoma in children and young adults. 1535 Mar

We describe a progressive mantle cell lymphoma (MCL) in which multicolor fluorescence in situ hybridization (M-FISH) on metaphases did not detect the characteristic t(11;14)(q13;q32), although translocations of chromosomes 11 with 15, and 14 with 15 were observed. When CCND1/IGH probes were hybridized to metaphases, however, cryptic fusion signals were detected on the der(11) and der(14) sites of CCND1 (11q13) and IGH (14q32), revealing a complex translocation involving chromosomes 11, 14, and 15. Interphase FISH with CCND1/IGH probes revealed varying patterns with one or two fusion signals, and some with no clear evidence of fusion. Loss of 17p and gain of 3q, known to be associated with disease progression in MCL, were detected with M-FISH and confirmed with the use of p53 and BCL6 probes together with comparative genomic hybridization, which detected also an interstitial deletion on 7p21. This case further illustrates the value of M-FISH in combination with fusion probes in elucidating complex cytogenetic abnormalities.
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PMID:Molecular cytogenetic study of a mantle cell lymphoma with a complex translocation involving the CCND1 (11q13) region. 1538 76

We tested a set of commercially available probes to determine the feasibility and accuracy of FISH in the detection of abnormalities in 13 patients with Chronic Lymphocytic Leukemia (CLL) with a particular aggressive clinical disease. We utilized three different probes for the 13q12-14 region, one for the centromeric region of chromosome 12, one for the P53 gene at 17p13.1 and one for 3'-5' IGH at 14q32, covering the entire region of IGH, thus potentially allowing to detect more rearrangements. Conventional cytogenetic study showed a normal karyotype in 8/13 patients. FISH was able to detect chromosomal abnormalities in 10/13 pts (85%): +12 in 4 pts (38%); del 13q in 4 (38%); del 17p in 3 (35%); del of 5'-IGH in 1 (15%). In conclusion FISH confirmed its ability to improve the detection of cytogenetic abnormalities especially in patients with an aggressive disease.
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PMID:Molecular cytogenetic analysis of B-CLL patients with aggressive disease. 1576 78

In contrast to nodal large B-cell lymphomas, recurrent chromosomal aberrations have been studied only in a small number of cases of primary cutaneous diffuse large B-cell lymphoma (PCDLBCL). We investigated 25 PCDLBCLs (classified according to the WHO-EORTC classification into PCDLBCL, leg-type, 8; and PCDLBCL, other, 17), using an interphase fluorescence in situ hybridization technique. All cases were analyzed for chromosomal aberrations commonly observed in nodal large B-cell lymphomas, including structural aberrations of the genes BCL2, BCL6, and c-MYC, and numerical aberrations of the chromosomes/genes 3, 7, 8, 11, 12, 13, 17, 18q, RB1, and p53. We observed genetic aberrations in 19 (76%) of 25 patients. The most frequent numerical aberrations were gains of chromosome 12 (7 of 25, 28%), 7 (5 of 25, 20%), 3 (5 of 25, 20%), 18q (3 of 25, 12%), 11 (3 of 25, 12%), X (3 of 25, 12%), and losses of chromosome/gene 17/p53 (3 of 25, 12%). BCL2, c-MYC, and BCL6 were rearranged with the IGH gene in 4 (16%), 1 (4%), and none (0%) of 25 cases, respectively. Most aberrations were homogeneously distributed among cases of PCDLBCL, leg-type and of PCDLBCL, other, cases located on the leg or at other body sites, cases with round and cleaved cell morphology, and Bcl-2+ and Bcl-2- cases. These results suggest that PCDLBCLs show similar chromosomal aberrations irrespective of classification, anatomic site, cell morphology, and Bcl-2 expression, and that many similarities between primary cutaneous and nodal diffuse large B-cell lymphomas can be observed.
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PMID:Genetic aberrations in primary cutaneous large B-cell lymphoma: a fluorescence in situ hybridization study of 25 cases. 1583 92

Activation of an oncogene via its juxtaposition to the IGH locus by a chromosomal translocation or, less frequently, by genomic amplification is considered a major mechanism of B-cell lymphomagenesis. However, amplification of an IGH/oncogene fusion, coined a complicon, is a rare event in human cancers and has been associated with poor outcome and resistance to treatment. In this article are descriptions of two cases of germinal-center-derived B-cell lymphomas with IGH/BCL2 fusion that additionally displayed amplification of an IGH/MYC fusion. As shown by fluorescence in situ hybridization, the first case contained a IGH/MYC complicon in double minutes, whereas the second case showed a BCL2/IGH/MYC complicon on a der(8)t(8;14)t(14;18). Additional molecular cytogenetic and mutation analyses revealed that the first case also contained a chromosomal translocation affecting the BCL6 oncogene and a biallelic inactivation of TP53. The second case harbored a duplication of REL and acquired a translocation affecting IGL and a biallelic inactivation of TP53 during progression. Complicons affecting Igh/Myc have been reported previously in lymphomas of mouse models simultaneously deficient in Tp53 and in genes of the nonhomologous end-joining DNA repair pathway. To the best of our knowledge, this is the first time that IGH/MYC complicons have been reported in human lymphomas. Our findings imply that the two mechanisms resulting in MYC deregulation, that is, translocation and amplification, can occur simultaneously.
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PMID:Amplification of IGH/MYC fusion in clinically aggressive IGH/BCL2-positive germinal center B-cell lymphomas. 1585 72

Burkitt-type acute leukemia cells were present in the bone marrow of a patient with B-prolymphocytic leukemia diagnosed from peripheral blood cell morphology. Immunophenotype analysis confirmed morphological patterns. Cytogenetic and fluorescence in situ hybridization (FISH) analysis showed an identical t(8;22)(q24;q21) with MYC locus rearrangement in blood and bone marrow cells, with additional chromosome abnormalities in the bone marrow. In addition, the loss of one copy of the TP53 gene and identical IGH DNA clonal rearrangements were shown with FISH and polymerase chain reaction analysis respectively in the two types of leukemic cells. These data indicated the common origin of the two coexisting leukemias and are the first example of such occurrence in a leukemic patient.
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PMID:Burkitt-type acute leukemia in a patient with B-prolymphocytic leukemia: evidence for a common origin. 1586 Mar 62

Clonally related composite lymphomas of Hodgkin's lymphoma (HL) and Non-Hodgkin's lymphoma (NHL) represent models to study the multistep transformation process in tumorigenesis and the development of two distinct tumors from a shared precursor. We analyzed six such lymphomas for transforming events. The HLs were combined in two cases with follicular lymphoma (FL), and in one case each with B-cell chronic lymphocytic leukemia, splenic marginal zone lymphoma, mantle cell lymphoma (MCL) and diffuse large B-cell lymphoma (DLBCL). In the HL/FL and HL/MCL combinations, BCL2/IGH and CCND1/IGH translocations, respectively, were detected in both the HL and NHL. No mutations were found in the tumor suppressor genes FAS, NFKBIA and ATM. The HL/DLBCL case harbored clonal replacement mutations of the TP53 gene on both alleles exclusively in the DLBCL. In conclusion, we present the first examples of molecularly verified IgH-associated translocations in HL, which also show that BCL2/IGH or CCND1/IGH translocations can represent early steps in the pathogenesis of composite HL/FL or HL/MCL. The restriction of the TP53 mutations to the DLBCL in the HL/DLBCL case exemplifies a late transforming event that presumably happened in the germinal center and affected the fate of a common lymphoma precursor cell towards development of a DLBCL.
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PMID:Insights into the multistep transformation process of lymphomas: IgH-associated translocations and tumor suppressor gene mutations in clonally related composite Hodgkin's and non-Hodgkin's lymphomas. 1597 55

Adult, de novo B-cell lymphomas meeting the WHO morphologic criteria for atypical Burkitt/Burkitt-like lymphoma cause diagnostic difficulty for pathologists because the genetic and clinical characteristics of this group of lymphomas have not been clearly defined. Thirty-one such lymphomas, designated as Burkitt-like lymphomas (BLL), were selected based on morphologic features and evaluated for immunophenotype, MYC and BCL2 status, and clinical features. Nine childhood Burkitt lymphomas (BL) and 87 adult, de novo diffuse large B-cell lymphomas (DLBL) were similarly evaluated for comparison. The BL group demonstrated uniform characteristics: all had Burkitt lymphoma morphology, an identical immunophenotype (positive for CD20, CD10, bcl-6, CD43, and p53; negative for CD138, CD23, bcl-2), high MIB-1 positivity, IGH/MYC translocation, no IGH/BCL2 translocation, and all patients were alive at the last follow-up. The BLL and DLBL groups were heterogeneous. Burkitt-like morphology alone correlated with decreased survival. IGH/MYC or IGL/MYC fusion was identified in 11 of 27 (41%) BLL and 4 of 76 (5%) DLBL and was associated with decreased survival in both groups. MIB-1 positivity did not correlate with morphology, MYC abnormalities, or survival. We propose that adult B-cell lymphomas with BLL morphology are a phenotypically and genetically heterogeneous group of aggressive lymphomas, biologically distinct from childhood BL. Until biologically accurate subgroups within this morphologically defined group are identified, it is appears that both recognition of BLL morphology and direct evaluation for the presence of MYC fusion to immunoglobulin genes are important for identification of adult patients with poorer prognosis than those with DLBL.
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PMID:Adult B-cell lymphomas with burkitt-like morphology are phenotypically and genotypically heterogeneous with aggressive clinical behavior. 1632 38


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