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

Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL) account for nearly all pediatric nonlymphoblastic B-cell lymphomas. Because clinical behavior, prognosis, and response to therapy might differ, diagnostic accuracy is important. Morphologic examination often is sufficient, but occasionally, diagnostic ancillary studies are required. In adults, immunophenotyping is useful; however, pediatric data are limited. We characterized the immunohistochemical expression of 6 proteins (c-myc, CD10, bcl-6, bcl-2, CD138, and MIB-1) in pediatric BL (33 cases) and DLBCL (20 cases) with classic morphologic features. Significant differences in c-myc (BL, 30/33 [91%] vs DLBCL, 5/20 [25%]; P < .0001), bcl-2 (BL, 1/25 [4%] vs DLBCL, 7/19 [37%]; P < .02), and mean MIB-1 (BL, 99% vs DLBCL, 56%; P < .0001) expression were observed. There were no significant differences for CD10 (100% expression in BL and DLBCL), bcl-6 (BL, 23/33 [70%] vs DLBCL, 15/20 [75%]), or CD138 (no expression). Thus, pediatric BL and DLBCL have distinctive immunohistochemical profiles, and staining for c-myc, MIB-1, and bcl-2 might be useful in morphologically difficult cases.
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PMID:Comparative immunohistochemical analysis of pediatric Burkitt lymphoma and diffuse large B-cell lymphoma. 1502 43

Burkitt's lymphoma (BL) and its variants, including Burkitt-like lymphoma (BLL), can be difficult to distinguish morphologically and immunophenotypically from diffuse large B-cell lymphoma (DLBCL). Because the treatment of BL differs markedly from that of other types of non-Hodgkin's lymphoma (NHL), exact pathological diagnosis is crucial. We report 2 cases of patients with BL initially diagnosed as DLBCL. Due to clinical features typical of BL, long distance polymerase chain reaction (PCR) for detecting the t(8;14) translocation involving the c-myc proto-oncogene was performed on ascites lymphoma cells. Re-evaluation by a reference hematopathologist, together with long distance PCR in both patients revealing the t(8;14) translocation, resulted in diagnosis modification to BL and BLL. Consequently, the patients were treated with intense high-dose chemotherapy regimens including central nervous system (CNS) prophylaxis, and complete remission was initially achieved in both patients. Both BL and BLL should be considered in the differential diagnosis of DLBCL if abdominal spread with ascites and metabolic disorders are present. Long distance PCR analysis of ascites lymphoma cells for the detection of the BL-typical c-myc rearrangement offers a convenient and rapid possibility of diagnosis verification in atypical or borderline cases of BL.
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PMID:Long distance polymerase chain reaction of ascites lymphoma cells aids diagnosis establishment of abdominal Burkitt's lymphoma and Burkitt-like lymphoma. 1562 85

Burkitt's lymphoma is invariably associated with chromosomal translocations that juxtapose the c-myc proto-oncogene with regulatory elements of the immunoglobulin heavy (IgH) or light chain loci resulting in the deregulation of c-myc expression. However, the enhancer elements mediating c-myc deregulation in vivo remain largely unidentified. To investigate the role of the IgH 3'-enhancers in c-myc deregulation, we used gene targeting to generate knock-in mice in which four DNase I hypersensitive regions from the murine IgH 3'-region were integrated into the 5'-region of the c-myc locus. The IgH 3'-enhancers induced the up-regulation of c-myc expression specifically in B cells of IgH-3'-E-myc mice. After approximately 10 months, the mice developed a Burkitt-like B cell lymphoma with the phenotype of B220+, IgM+, and IgD(low). Analysis of immunoglobulin gene rearrangements indicated that the lymphoma cells were of clonal origin. The presence of a rapidly expanding population of B cells in the spleen and bone marrow of young knock-in mice at 2-4 months of age was observed. Premalignant splenic B cells of knock-in mice showed higher spontaneous and induced apoptosis; however, malignant B cells were more resistant to apoptosis. The p53-ARF-Mdm2 pathway was disabled in half of the lymphomas examined, in most cases through Mdm2 overexpression. Although c-myc expression was increased in premalignant B cells, the promoter shift from P2 to P1 was observed only in malignant B cells. Our studies demonstrate that the IgH 3'-enhancers play an important role in c-myc deregulation and B cell lymphomagenesis in vivo.
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PMID:Regulatory elements in the immunoglobulin heavy chain gene 3'-enhancers induce c-myc deregulation and lymphomagenesis in murine B cells. 1568 98

Histological, clinical and immunohistochemical analysis of 6 cases of primary liver lymphomas (PLL) are presented. PLL represents 4.3% of primary malignant liver tumors diagnosed in our department. The patients were relatively young people, who despite the presence of a large tumor, were in good general health status. There were no signs of scirrhosis, and cancer markers were normal. All lymphomas were CD20, CD79a, BAX positive, CD3, CD30, EMA, CD10, CD5, CD59, c-myc, Bcl2, EBV(LMP), CK negative. The proliferation index (Ki67) was high, ranging from 50-100%. In two cases positive staining for Bcl6 and in another one for cyclin D1 was obtained. The major histological type of the tumor was diffuse large B-cell lymphoma. Positive immunohistochemical results with BAX and the lack of Bcl2, c-myc and CD59 are associated with better prognosis. We have not confirmed the value of Bcl6 and CD10 stains as a predictor of poor outcome. Despite clinically advanced stage at the time of diagnosis, if treated appropriately, the primary lymphoma of the liver has relatively good prognosis (five of our patients are alive).
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PMID:Primary lymphoma of the liver -- morphological and clinical analysis of 6 cases. Success of aggressive treatment. 1587 91

We report an instructive case of diffuse large B-cell lymphoma presenting as acute heart failure. A 69-year-old human immunodeficiency virus-negative man was admitted to our hospital for general fatigue. A computed tomographic scan of the chest and abdomen showed pericardial effusion, but there was no evidence of tumor masses, lymph node enlargement, or hepatosplenomegaly. During the chemotherapy, increased lactate dehydrogenase and pleural effusion appeared. The tumor cells in the effusion showed positivity for CD5, CD19, CD20, kappa chain, and Bcl-2 and negativity for CD10 and CD23. The chromosomes showed t(8;14)(q24;q32) with c-myc/immunoglobulin (Ig)H rearrangement, and the MIB-1 index was not high (60%). Neither human herpes virus 8 nor Epstein-Barr virus DNA was detected in the cells by polymerase chain reaction. The response to chemotherapy was very poor, and the patient died 4 months after the diagnosis. A spectrum of the symptoms of CD5+ lymphoma encompasses pericardial effusion and also can accompany c-myc/IgH rearrangement.
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PMID:CD5+ diffuse large B-cell lymphoma with c-myc/IgH rearrangement presenting as primary effusion lymphoma. 1591 62

To date, more than 200 microRNAs have been described in humans; however, the precise functions of these regulatory, non-coding RNAs remains largely obscure. One cluster of microRNAs, the mir-17-92 polycistron, is located in a region of DNA that is amplified in human B-cell lymphomas. Here we compared B-cell lymphoma samples and cell lines to normal tissues, and found that the levels of the primary or mature microRNAs derived from the mir-17-92 locus are often substantially increased in these cancers. Enforced expression of the mir-17-92 cluster acted with c-myc expression to accelerate tumour development in a mouse B-cell lymphoma model. Tumours derived from haematopoietic stem cells expressing a subset of the mir-17-92 cluster and c-myc could be distinguished by an absence of apoptosis that was otherwise prevalent in c-myc-induced lymphomas. Together, these studies indicate that non-coding RNAs, specifically microRNAs, can modulate tumour formation, and implicate the mir-17-92 cluster as a potential human oncogene.
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PMID:A microRNA polycistron as a potential human oncogene. 1600 26

Morphologic features of Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL) overlap. No single phenotypic marker or molecular abnormality is pathognomonic. We tested a panel of 8 germinal center (GC) and activated B-cell (ABC) markers for their ability to separate BL and DLBCL. We diagnosed 16 BL and 39 DLBCL cases from 21 patients with AIDS and 34 without AIDS based on traditional morphologic criteria, Ki-67 proliferative index, and c-myc rearrangement (fluorescence in situ hybridization). After immunohistochemically staining tissue microarrays of BL and DLBCL for markers of GC (bcl-6, CD10, cyclin H) and ABC (MUM1, CD138, PAK1, CD44, bcl-2), we scored each case for the percentage of positive cells. Hierarchical clustering yielded 2 major clusters significantly associated with morphologic diagnosis (P < .001). For comparison, we plotted the sum of the GC scores and ABC scores for each case as x and y data points. This revealed a high-GC/low-ABC group and a low-GC/high-ABC group that were associated significantly with morphologic diagnosis (P < .001). Protein expression of multiple GC and ABC markers can separate BL and DLBCL.
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PMID:Germinal center and activated b-cell profiles separate Burkitt lymphoma and diffuse large B-cell lymphoma in AIDS and non-AIDS cases. 1620 84

Ovarian involvement as an initial manifestation of lymphoma, without detectable extraovarian disease, is a rare occurrence. The diagnosis of ovarian lymphoma is almost invariably unsuspected until the tumor has been examined histologically. A 25-year-old null gravid woman presented with abdominal distension. Presence of abnormal lymphoid cells in pleural effusion led to presurgical assumption that the pelvic mass noted on computerized tomography examination might be an ovarian lymphoma. We performed left salpingo-oophorectomy. Clinical, histologic, and molecular examination revealed Burkitt's lymphoma of the ovary with c-myc gene rearrangement and mRNA expression of multiple cytokines. She received dose-intensified combination chemotherapy. She is alive and free of disease 30 months after the diagnosis. Immunophenotype and molecular findings allowed reliable discrimination of Burkitt's lymphoma from diffuse large B-cell lymphoma and other lymphomas. If an ovarian tumor is solid and suspected to be of lymphoid origin, we suggest that it is necessary to obtain samples for genetic examination at surgery. This strategy often provides important information to establish therapeutic regimen and predict patient prognosis.
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PMID:Ovarian Burkitt's lymphoma diagnosed by a combination of clinical features, morphology, immunophenotype, and molecular findings and successfully managed with surgery and chemotherapy. 1651 18

Human rck/p54, a product of the gene cloned at the breakpoint of t(11; 14) (q23;q32) chromosomal translocation on 11q23 in B-cell lymphoma, is a member of the DEAD-box RNA helicase family. Here, the crystal structure of Nc-rck/p54, the N-terminal core domain of rck/p54, revealed that the P-loop in motif I formed a closed conformation, which was induced by Asn131, a residue unique to the RCK subfamily. It appears that ATP does not bind to the P-loop. The results of dynamic light scattering revealed to ATP-induced conformational change of rck/p54. It was demonstrated that free rck/p54 is a distended molecule in solution, and that the approach between N-terminal core and C-terminal domains for ATP binding would be essential when unwinding RNA. The results from helicase assay using electron micrograph, ATP hydrolytic and luciferase assay showed that c-myc IRES RNA, whose secondary structure regulates IRES-dependant translation, was unwound by rck/p54 and indicated that it is a good substrate for rck/p54. Over-expression of rck/p54 in HeLa cells caused growth inhibition and cell cycle arrest at G2/M with down-regulation of c-myc expression. These findings altogether suggest that rck/p54 may affect the IRES-dependent translation of c-myc even in the cells.
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PMID:Structural insight of human DEAD-box protein rck/p54 into its substrate recognition with conformational changes. 1661 Dec 46

We have previously reported functional alterations in vitro in the hematopoietic compartment of patients with diffuse large B-cell lymphoma (DLBCL). In the present study, we assessed the presence of molecular alterations in hematopoietic cells derived from DLBCL marrow. Accordingly, the expression of four genes (i.e. ice, bcl-2, c-myc and p53) was assessed both, at the mRNA and protein levels, in three cell populations: (i) population I, consisting of morphologically recognizable precursor and mature cells; (ii) population II, enriched for CD34+ Lineage-negative (Lin-) cells; and (iii) population III, enriched for CD34+ CD38- Lin- cells. By using a multiplex reverse transcriptase-polymerase chain reaction system, we observed reduced expression of bcl-2 in population I, and c-myc in populations I and II from lymphoma marrow compared to their normal counterparts. On the other hand, expression of ice and p53 was not significantly different when comparing normal and DLBCL samples. At the protein level, all four molecules were expressed in a higher proportion of samples from DLBCL patients than in marrow samples from normal subjects. Interestingly, these proteins were expressed predominantly in primitive cells (population III), whereas the proportion of positive samples was reduced in population II, and even more in population I. Taken together, our results indicate that, in DLBCL, molecular alterations are present in hematopoietic cells from bone marrow, including morphologically recognizable precursor and mature cells, as well as primitive hematopoietic progenitors (CD34+ cells). To date, the physiological implications of these alterations are still unclear, and further studies should be undertaken to address this issue.
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PMID:Expression of ice, bcl-2, c-myc and p53 in different bone marrow cell populations from patients with diffuse large B-cell lymphoma. 1669 May 25


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