UNIPROT:P04637 - FACTA Search

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

Diffuse large B-cell lymphoma (DLCL) exhibits heterogeneous clinical features and varies markedly in response to treatment and prognosis. Because apoptosis-related proteins may play an important role in predicting the prognosis of DLCL, the current study investigated the prognostic significance of a high level of bcl-2, bax, and p53 expression in relation to clinical characteristics in patients with DLCL. Paraffin-embedded specimens from 94 patients with de novo DLCL were analyzed immunohistochemically for bcl-2, bax, and p53 gene expression. Cases with a positive immunohistological stain in more than 50% of the tumor cells were considered to have DLCL-positive expression. Patients were treated optimally, i.e., with radiotherapy including brief cycles of CHOP or CHOP-like regimens for patients with stage 1-2A diseases and with at least 6 cycles of CHOP or CHOP-like regimens for stage 2B-4 diseases. The responses to therapy and survival were then analyzed in 94 uniformly staged patients. bcl-2 expression was identified in 24 patients (26.4%), bax expression in 35 patients (37.6 %), and p53 expression in 21 patients (22.6%). bax expression proved to be a statistically significant prognostic factor in predicting the overall survival (OS) (P = 0.0015) and disease-free survival (DFS) (P = 0.0052), regardless of other clinical factors or immunohistological results. There was no significant difference in the OS (P = 0.0682) or DFS (P = 0.088) between the bcl-2-positive (n = 24) and bcl-2-negative (n = 67) groups. However, bcl-2 expression was found to be unfavorably associated with the OS (P = 0.0054) in a confined group with low (n = 51) or low intermediate (n = 22) IPI scores. The expression of p53 exhibited no statistical correlation with the OS or DFS. A multivariate analysis revealed that IPI score, bulky mass, and bax expression were all significantly associated with the DFS or OS. bax and bcl-2 should be considered as independent biologic prognostic parameters in DLCL, thereby aiding in the identification of patient risk groups. As such, bcl-2-positive patients with a low or low intermediate IPI score, or without a high level of bax expression could be candidates for more intensive therapy or alternative therapeutic approaches.
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PMID:Prognostic significance of bcl-2, bax, and p53 expression in diffuse large B-cell lymphoma. 1274 11

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

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin's lymphoma. Although the presence of p53 gene mutations has been considered as a bad prognostic feature in DLBCL, its clinical significance is still controversial. The aims of this study were: detect the presence of mutations in exons 5 to 9 of the p53 gene and correlate it to prognosis in DLBCL. Fifty-one DLBCL patients were enrolled in this study. Expression of p53 was evaluated by immunohistochemistry. The screening of p53 mutations was performed using PCR-SSCP methods. Cases showing a mobility shift on SSCP electrophoresis were analyzed by automatic sequencing. We could identify 8 missense mutations in 6 of 48 cases (12.5%). In addition, we found a known polymorphism at codon 213 and 2 instances of silent mutations. Of all mutations/polymorphisms found, 7 (64%) were localized in codons previously described as p53 hot spots in NHL cases. Of the remaining alterations (4 or 36%), 2 mutations were localized in codons previously described as hot spots for p53 in other tumors and 2 (codon 142 of the exon 5 and codon 195 of the exon 6), in codons not described as hot spots for p53 up to now. The presence of missense mutations in exons 5 to 9 of p53 gene had adverse impact on overall survival (P = 0.020). Cox's Regression Model identified that high-risk International Prognostic Index (IPI) and p53 gene mutations have independent negative impact on OS. Therefore, the association of IPI with cellular factors, such as p53 mutation, can be very helpful in deciding when we should indicate more aggressive therapies in patients with DLBCL, to somehow increase the chance of cure in these patients.
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PMID:Detection and possible prognostic relevance of p53 gene mutations in diffuse large B-cell lymphoma. An analysis of 51 cases and review of the literature. 1537 Feb 52

Rearrangements involving the 1p36 chromosomal region occur frequently in NHL, suggesting the existence of tumor suppressor gene(s) that are important in lymphomagenesis. p73 is closely related to the tumor suppressor p53 and maps to the chromosome 1p36 region. Here we report heterozygous deletions of the p73 locus in 25% of FL and 27% of DLBCL cases, as detected by FISH. Immunohistochemical analysis showed that four out of five cases with p73 deletions also exhibited increased Ki67 expression, indicating higher proliferation rates of the tumor cells. Our results demonstrate a high proportion of p73 locus specific deletions in NHL and suggest that deletion of this locus may play a role in the progression of NHL.
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PMID:The p73 locus is commonly deleted in non-Hodgkin's lymphomas. 1547 76

A major challenge in cancer diagnosis from microarray data is the need for robust, accurate, classification models which are independent of the analysis techniques used and can combine data from different laboratories. We propose such a classification scheme originally developed for phenotype identification from mass spectrometry data. The method uses a robust multivariate gene selection procedure and combines the results of several machine learning tools trained on raw and pattern data to produce an accurate meta-classifier. We illustrate and validate our method by applying it to gene expression datasets: the oligonucleotide HuGeneFL microarray dataset of Shipp et al. (www.genome.wi.mit.du/MPR/lymphoma) and the Hu95Av2 Affymetrix dataset (DallaFavera's laboratory, Columbia University). Our pattern-based meta-classification technique achieves higher predictive accuracies than each of the individual classifiers , is robust against data perturbations and provides subsets of related predictive genes. Our techniques predict that combinations of some genes in the p53 pathway are highly predictive of phenotype. In particular, we find that in 80% of DLBCL cases the mRNA level of at least one of the three genes p53, PLK1 and CDK2 is elevated, while in 80% of FL cases, the mRNA level of at most one of them is elevated.
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PMID:Robust diagnosis of non-Hodgkin lymphoma phenotypes validated on gene expression data from different laboratories. 1636 26

A member of the family of p53-related genes, p63 plays a role in regulating epithelial proliferation and differentiation programs, but the pathological and clinical meaning of p63 in B-cell lymphoma has not been elucidated. We investigated the expression pattern of p63 in B-cell malignancies, and evaluated the correlation between the expression of p63 and other germinal center markers. Ninety-eight B-cell lymphomas (28 FCL, 5 MCL, and 65 DLBCL) were analyzed by immunohistochemical examination for p63, bcl-6, CD10 and MUM-1 proteins, and for rearrangement of bcl-2/IgH. Expression of p63 was observed in the nuclei of tumor cells obtained from 15 of 28 (54%) FCL, 22 of 65 (34%) DLBCL, but none of 5 MCL. In DLBCL, the expression of p63 and bcl-6 showed a significant correlation (P < 0.02), but no correlation was observed between p63 and expression of CD10, MUM-1, or bcl-2/IgH rearrangement. RT-PCR revealed that TAp63alpha-type transcripts, a possible negative regulator of transcriptional activation of p21 promoter, were major transcripts in B-cell lymphoma tissues. As for prognostic significance, only patients in the p63 positive group of FCL died, and in the non-germinal center group, the p63 positive cases appeared to have inferior overall survival than other groups in DLBCL. Our preliminary results suggested that p63 expression is a disadvantageous factor for prognosis in this subgroup of B-cell lymphomas.
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PMID:Clinico-pathological characteristics of p63 expression in B-cell lymphoma. 1691 93

In the last decades, considerable changes in the classification of lymphomas have been made. In addition to morphology and immunohistochemistry, the last WHO (2001) classification also utilizes cytogenetics and molecular biology. In many cases classification notices oncogenic mechanisms. The authors describe some differences in immunophenotype in certain entities: chronic lymphocytic leukaemia/small lymphocytic lymphoma--CLL/SLL, follicular lymphoma--FL, mantle cell lymphoma--MCL, diffuse large B-cell lymphoma--DLBCL, and anaplastic large cell lymphoma--ALCL, mainly with respect to prognosis. The authors point out to heterogeneity within the individual types of lymphomas from the point of view of morphology, immunohistochemistry and molecular biology. Recently it has been shown, that differences in prognosis are not limited to individual nosologic entities, but also may be found within the particular category of lymphoma. For example, CLL/SLL is divided in two different subunits according to mutational status of variable segment (VH) of the immunoglobulin heavy chain gene. The cases with unmutated VH segment display progressive disease which is in contrast to cases with the same morphology but with mutated VH segment. Similar differences were found in MCL. Attention is drawn to oncogenic and apoptosis-regulating mechanisms, such as gene p53 and the Bcl-2 family.
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PMID:[Non-Hodgkin's lymphomas (from Rappaport to WHO 2001 and nowadays). Review]. 1762 75

Diffuse large B-cell lymphomas (DLBCL) display defects in cell cycle and apoptosis regulation. Therefore, the immunohistochemical expression patterns of the proteins p14, p21, Hdm2 and cyclin D2 were analyzed in relation to the previously reported expression of other major cell cycle proteins (p53, Rb, p16, p27, Ki-67 and cyclins A, B1, D2, D3 and E), apoptosis-associated proteins (bcl2, bcl-xl, bax, bak, bad and bid) and the B-cell differentiation immunophenotypes. Expression of the proteins p14, p21, Hdm2 and cyclin D2 was observed in 62/71 (87%), 22/76 (29%), 35/74 (47%) and 11/77 (14%) cases, respectively. Immunohistochemical alterations of the p53 (p53-Hdm2-p21-p14), Rb (Rb-p16-cyclin D [D2 or D3]) and p27 (p27-cyclin E) pathways were found in 56/77 (73%), 53/79 (67%) and 54/79 (68%) cases, respectively. Concomitant alterations of the p53-Rb, p53-p27 and Rb-p27 pathways were found in 40/77 (52%), 38/77 (50%) and 36/79 (46%) cases, respectively. Three concomitant alterations of the p53-Rb-p27 pathways were found in 28/79 (35%) cases. The main findings of the present study were the following: alterations of the p27 pathway were associated with higher expression of Ki-67 (p = 0.023); concomitant alterations of the p53Rb pathways and the p53-p27 pathways were associated with higher expression of cyclin A (p = 0.015 and p = 0.021, respectively) and concomitant alterations of the p53, Rb and p27 pathways were associated with higher expression of cyclin A (p = 0.013). Since cyclin A supports DNA replication, centrosome duplication and mitosis, these findings indicate that concomitant alterations of the p53, Rb and p27 pathways in DLBCL may have cooperative effects resulting in increased neoplastic cell proliferation. This might explain, at least partially, the association between concurrent aberrations of the p53, Rb and p27 pathways and aggressive clinical behavior in DLBCL.
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PMID:Alterations of the p53, Rb and p27 tumor suppressor pathways in diffuse large B-cell lymphomas. 1769 24

Primary diffuse large B-cell lymphomas of different immune-privileged sites (IP-DLBCLs) share many clinical and biological features, such as a relatively poor prognosis, preferential dissemination to other immune-privileged sites, and deletion of the HLA region, which suggests that IP-DLBCL represents a separate entity. To further investigate the nature of IP-DLBCL, we investigated site-specific genomic aberrations in 16 testicular, nine central nervous system (CNS), and 15 nodal DLBCLs using array CGH. We also determined minimal common regions of gain and loss. Using robust algorithms including multiple testing procedures and the ACE-it script, which is specifically designed for this task, the array CGH data were combined with gene expression data to explore pathways deregulated by chromosomal aberrations. Loss of 6p21.32-p25.3, including the HLA genes, was associated with both types of IP-DLBCL, whereas gain of 2p16.1-p25.3 was associated with nodal DLBCL. Gain of 12q15-q21.1 and 12q24.32-q24.33 was associated with CNS DLBCL and gain of 19q13.12-q13.43 with testicular DLBCL. Analysis of candidate genes in site-specific regions and minimal common regions revealed two major groups of genes: one involved in the immune response, including regulation of HLA expression, and the other involved in apoptosis, including the p53 pathway. Many of these genes were also involved in homozygous deletions or high-level gains. The presence of both shared and site-specific aberrations in CNS and testicular DLBCLs underlines the concept of IP-DLBCL but also indicates that IP-DLBCLs of the CNS and testis do not form a single entity. The observed aberrations emphasize the importance of the deregulation of anti-tumour immune response and apoptosis pathways.
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PMID:Genomic alterations and gene expression in primary diffuse large B-cell lymphomas of immune-privileged sites: the importance of apoptosis and immunomodulatory pathways. 1872 69

Primary bone diffuse large B-cell lymphomas (PB-DLBCL) are uncommon extranodal lymphomas. Herein, we report the clinical, pathologic, immunohistochemical, and molecular features of 21 cases of PB-DLBCL. The mean age of the patients was 54 years (range: 13 to 85 y). The male and female ratio was 1.6:1. The tumors consisted of diffuse sheets of large atypical cells or a polymorphous mixture of small-to-large cells with large multilobated nuclei, fine chromatin, and inconspicuous to prominent nucleoli. Twelve (57%) cases were non-germinal center B (GCB) and 9 (43%) were GCB subtype based on immunohistochemical classification. B-cell lymphomas (BCL)-2 was positive in 17/21 (81%), TP53 in 11/21 (52%) positive and the mean MIB-1 index was 57%. Polymerase chain reaction showed 10 cases with immunoglobulin heavy-chain (IGH) and 4 cases with IGH/BCL-2 gene rearrangement. The fluorescence in-situ hybridization analyses showed 14% of cases with BCL-6, 19% of cases with BCL-2, and 9% of cases with C-MYC gene rearrangement. Age <60 years and complete response to initial treatment were significant predictors of survival outcome (P< or =0.05). Even though no association was observed between the subtype of PB-DLBCL (GCB vs. non-GCB), BCL2, TP53, MIB1 index and overall survival (P>0.05), due to small sample size, and variability in treatment received, this analysis may be interpreted with caution.
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PMID:Primary bone diffuse large B-cell lymphoma: clinicopathologic study of 21 cases and review of literature. 1967 54

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