Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acquired immunodeficiency syndrome (AIDS)-associated non-Hodgkin's lymphomas (AIDS-NHL), a major source of morbidity and mortality among AIDS patients, are derived from B cells and can be classified into two main histologic categories, small noncleaved cell lymphoma (SNCCL) and diffuse large-cell lymphoma (DLCL). DLCL includes two histologic subsets, ie, large noncleaved cell lymphoma (LNCCL) and large cell-immunoblastic plasmacytoid lymphoma (LC-IBPL). Several studies have shown that AIDS-SNCCL is associated with the clonal accumulation of multiple genetic lesions, including Epstein-Barr virus (EBV) infection, activation of the c-MYC and RAS oncogenes, as well as inactivation of the p53 tumor suppressor gene at variable frequencies. On the contrary, the molecular pathogenesis of AIDS-DLCL is largely obscure, because no genetic lesion other than EBV infection has been specifically identified in this group. In this study, we have tested a panel of 40 AIDS-NHL for structural alterations of BCL-6, a putative proto-oncogene that is frequently altered in DLCL in the immunocompetent host. Our results show that rearrangements of BCL-6 are present in 20% of AIDS-DLCL (5 of 24), including 2 of 8 LNCCL and 3 of 16 LC-IBPL, but in no case of AIDS-SNCCL. BCL-6 rearrangements were detected both in the presence and in the absence of EBV infection of the tumor clone, but in no case were associated with activation of c-MYC or mutations of p53. These data identify a novel genetic lesion in AIDS-DLCL and corroborate the notion that lymphomagenesis in AIDS follows two distinct molecular pathways that are associated with the development of histologically distinct types of AIDS-NHL.
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PMID:Rearrangements of the BCL-6 gene in acquired immunodeficiency syndrome-associated non-Hodgkin's lymphoma: association with diffuse large-cell subtype. 802 68

Epidemiological evidence indicates that a sexually transmitted agent might be involved in the etiopathogenesis of Kaposi's sarcoma (KS). The prevalence of human papillomaviruses (HPV) in KS has been the focus of several investigations that have reported conflicting data. In addition, mutations of the p53 gene, which are the most frequent genetic changes found in human tumors, are absent in HPV-positive cervical carcinomas leading to the hypothesis that the function of p53 in HPV-positive tumors is inactivated through binding to the E6 viral gene product. Thus, the present study was designed to investigate the presence of HPV and p53 gene mutations in 17 formalin-fixed, paraffin-embedded KS [7 acquired immunodeficiency syndrome-KS (AIDS-KS) and 10 classic KS] specimens. HPV 6 DNA was detected in an AIDS-KS specimen, and HPV 16 DNA was found in 3 classic KS specimens. Heterozygous mutations of the p53 gene were detected in five (24%) KS samples. No p53 mutations were detected in HPV-positive KS. The p53 mutations were mainly transversions (four of five). These data indicate that HPV may contribute to the pathogenesis of some cases of KS and that p53 alteration may represent a key event in the progression of the malignancy.
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PMID:Occurrence of human papillomavirus and p53 gene mutations in Kaposi's sarcoma. 803 Feb 71

Mutations of the p53 tumor suppressor gene are among the most common genetic alterations found in many different human malignancies, including those of the colon, lung, and breast. Alterations in wild-type p53 lead to loss of the suppressor function and thus contribute to tumorigenesis. The potential role of p53 mutations in a sampling of B-cell lymphomas, the majority of which were associated with Epstein-Barr virus (EBV), was investigated. Twenty-six biopsy specimens from immunocompromised patients, including allograft recipients and patients with AIDS, Wiscott-Aldrich syndrome, and human T-cell leukemia virus type 1 infection, in comparison with three Burkitt lymphomas and four Burkitt lymphoma cell lines were analyzed. Mutation in p53 was detected in all four Burkitt lymphoma cell lines as well as the three Burkitt lymphoma biopsy specimens. In patients with AIDS, 5 of 10 lymphomas were EBV positive, and 1 had a mutation in p53. Mutation in p53 was not detected in 14 EBV-positive lymphomas which arose in transplant recipients. These data indicate that with the exception of Burkitt lymphomas, p53 mutations are not involved in the majority EBV-positive B-cell lymphomas which develop in immunocompromised patients.
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PMID:Alterations of the p53 gene in Epstein-Barr virus-associated immunodeficiency-related lymphomas. 810 96

Acquired immunodeficiency syndrome-associated non-Hodgkin's lymphomas represent a significant and formidable clinical problem. They also represent an important biologic model for investigating the development and progression of high-grade malignant lymphomas and for studying lymphomas that develop in the setting of immune deficiency. A vast majority of non-Hodgkin's lymphomas exhibit clonal immunoglobulin gene rearrangements and, hence, are B-cell neoplasms. Most express B-cell phenotypes, but a minority, predominantly body cavity-based tumors, express indeterminate phenotypes. AIDS-associated non-Hodgkin's lymphomas do not contain HIV. However, approximately 40% of systemic non-Hodgkin's lymphomas, predominantly those with immunoblastic plasmacytoid morphology, and essentially 100% of primary central nervous system AIDS-associated non-Hodgkin's lymphomas contain Epstein-Barr virus. The c-myc protooncogene is rearranged in approximately 80% of systemic cases, predominantly in those with Burkitt's and Burkitt's-like morphology. Point mutations of the ras gene are detectable in approximately 15% of systemic cases. The p53 tumor-suppressor gene is mutated in approximately two thirds of systemic AIDS-associated Burkitt's and Burkitt's-like non-Hodgkin's lymphomas. The retinoblastoma tumor-suppressor gene does not appear to be mutated or deleted in AIDS-associated non-Hodgkin's lymphomas. In summary, various genetic lesions occur in AIDS-associated non-Hodgkin's lymphomas, which appear to vary according to the anatomic site of disease (systemic vs central nervous system vs body cavity) and the histopathology (Burkitt's vs immunoblastic vs large cell). Further active investigation is necessary to determine the role of these and possibly other genetic lesions in AIDS lymphomagenesis.
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PMID:Biologic aspects of AIDS-associated non-Hodgkin's lymphoma. 821 97

Programmed cell death (apoptosis) is a normal process by which cells are eliminated during normal embryonic development and in adult life. Disruption of this normal process resulting in illegitimate cell survival can cause developmental abnormalities and facilitate cancer development. Normal cells require certain viability factors and undergo programmed cell death when these factors are withdrawn. The viability factors are required throughout the differentiation process from immature to mature cells. Although many viability factors are also growth factors, viability and growth are separately regulated. Viability factors can have clinical value in decreasing the loss of normal cells including the loss that occurs after irradiation, exposure to other cytotoxic agents or virus infection including AIDS. There is no evidence that occurs after irradiation, exposure to other cytotoxic agents or virus infection including AIDS. There is no evidence that cancer cells are immortal. Programmed cell death can be induced in leukemic cells by removal of viability factors, by cytotoxic therapeutic agents, or by the tumor-suppressor gene wild-type p53. All these forms of induction of programmed cell death in leukemic cells can be suppressed by the same viability factors that suppress programmed cell death in normal cells. A tumor-promoting phorbol ester can also suppress this death program. The induction of programmed cell death can be enhanced by deregulated expression of the gene c-myc and suppressed by the gene bcl-2. Mutant p53 and bcl-2 suppress the enhancing effect on cell death of deregulated c-myc, and thus allow induction of cell proliferation and inhibition of differentiation which are other functions of deregulated c-myc. The suppression of cell death by mutant p53 and bcl-2 increases the probability of developing cancer. The suppression of programmed cell death in cancer cells by viability factors suggests that decreasing the level of these factors may increase the effectiveness of cytotoxic cancer therapy. Treatments that downregulate the expression or activity of mutant p53 and bcl-2 in cancer cells should also be useful for therapy.
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PMID:Control of programmed cell death in normal and leukemic cells: new implications for therapy. 832 19

p53 mutations are found in a variety of neoplasia. B-immunoblastic lymphoma (BIBL) is a rapidly progressive, aggressive lymphoma. As patients with acquired immunodeficiency syndrome (AIDS) live longer, BIBL is becoming an increasing problem. We asked three questions in our study. What is the frequency of p53 mutations in BIBL? Is it more frequent in patients with AIDS? Can immunohistochemical staining of lymph nodes for expression of p53 substitute for mutational analysis of p53 to detect lymphomas with mutated p53? Exons 5, 6, 7, 8 of the p53 gene (hot-spots for mutations) were amplified and examined for mutations by single-strand conformation polymorphism (SSCP) analysis. Altered migration was observed in 7 of 52 BIBL samples. Of these, 4 of 25 were from individuals infected with human immunodeficiency virus (HIV) and 3 of 27 were not infected with HIV. Direct sequencing of amplified material confirmed the presence of mutations in exons 5, 7, 8 of p53. A total of 26 BIBL as well as other lymphoma/leukemia samples, stained strongly by immunohistochemistry with three antibodies directed against human p53. Five of 6 BIBL samples with p53 mutations stained strongly for p53, but 20 lymphoma samples with no detectable p53 mutations also stained strongly for p53. Of note, however, 10 hyperplastic, nonmalignant lymph nodes from individuals either infected or not infected with HIV had negligible staining for p53 protein. In conclusion, p53 mutations occur in about 14% BIBL samples; the frequency of p53 mutations in BIBL in individuals with and without AIDS was similar. Positive p53 immunohistochemistry did not correlate with detectable p53 mutations in the same tissue, but positive immunohistochemical staining for p53 was only found in neoplastic lymph nodes. This latter finding provides a strong warning that p53 immunochemistry with available reagents cannot be used to determine which tumors have mutations of p53.
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PMID:Mutation and protein expression of p53 in acquired immunodeficiency syndrome-related lymphomas. 833 55

Non-Hodgkin's lymphoma (NHL) develops in about 5% to 10% of acquired immunodeficiency syndrome (AIDS) patients. The vast majority of AIDS-NHL are clinically aggressive B-cell NHL that are histologically classified as small noncleaved cell lymphoma (SNCCL), large cell immunoblastic plasmacytoid lymphoma (LC-IBPL), and large noncleaved cell lymphoma (LNCCL). In an attempt to understand the molecular pathogenesis of these tumors, we have investigated the involvement of dominantly acting oncogenes (c-myc, N-, K-, H-Ras), tumor suppressor genes (p53, RB1), and Epstein-Barr virus (EBV) infection in 27 AIDS-NHL samples (16 SNCCL, 5 LC-IBP, and 6 LNCCL). The following lesions were detected in AIDS-NHL: EBV infection (10/24; 41.6%), c-myc rearrangement (19/24; 79.1%), Ras mutation (4/27; 14.8%), and p53 loss/mutation (10/27; 37.0%). These lesions are not uniformly distributed, but, rather, cluster with specific types of AIDS-NHL: EBV infection is preferentially associated with LC-IBPL (4/4; 100%), while it is present in only a fraction of SNCCL (5/16; 31.2%) and LNCCL (1/4; 25%); c-myc oncogene activation clusters with SNCCL (16/16; 100%), whereas it is less frequent in LC-IBPL (1/4; 25%) and LNCCL (2/4; 50%); p53 inactivation is restricted to SNCCL (10/16; 62.5%) and consistently associated with c-myc activation. These data show that AIDS-NHL are associated with multiple genetic lesions that involve both proto-oncogenes and tumor suppressor genes and may accumulate in the relatively short period of time (4 to 6 years) between human immunodeficiency virus infection and AIDS-NHL development. These genetic lesions differ in the various AIDS-NHL subtypes, suggesting the involvement of distinct molecular pathway.
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PMID:Multiple genetic lesions in acquired immunodeficiency syndrome-related non-Hodgkin's lymphoma. 838 Feb 52

Lymphoma represents a major source of morbidity and mortality among AIDS patients. AIDS-associated non-Hodgkin lymphomas (AIDS-NHL) are almost invariably B-cell derived, are classified as high or intermediate grade lymphomas, and display three main histologic types: namely, small non-cleaved cell lymphoma (SNCCL), large cell immunoblastic plasmacytoid lymphoma (LC-IBPL), and large cell lymphoma (LCL). Here we report the in vitro establishment of three new AIDS-NHL cell lines (termed HBL-1, HBL-2, and HBL-3) derived from three AIDS-SNCCL patients differing in primary tumor sites and risk factors for HIV infection. The derivation of the cell lines from the original tumor clones was established by immunophenotypic and molecular genetic analysis. These cell lines display clonal immunoglobulin gene rearrangement, express surface immunoglobulin and B-cell restricted markers, and exhibit a phenotype consistent with SNCCL. Monoclonal Epstein-Barr virus infection was found in only one of the cell lines (HBL-1). Cytogenetic analysis demonstrated the presence of a chromosomal translocation involving the c-myc proto-oncogene and an immunoglobulin locus in all three cell lines. The pattern of genetic lesions detected in HBL-1, HBL-2, and HBL-3 reflects that found in primary AIDS-SNCCL and includes activation of the c-myc oncogene as well as inactivation of the p53 tumor suppressor gene. These cell lines should prove useful in studies of the biological, immunological, and viral factors involved in AIDS-associated lymphomagenesis.
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PMID:In vitro establishment of AIDS-related lymphoma cell lines: phenotypic characterization, oncogene and tumor suppressor gene lesions, and heterogeneity in Epstein-Barr virus infection. 841 24

Limited information is current available on the molecular and immunophenogenotypic characteristics of CD30-positive anaplastic large cell (ALC) lymphomas occurring in human immunodeficiency virus (HIV)-infected individuals. To address this issue, the authors have undertaken a combined analysis of these lymphomas in a comparison with other Epstein-Barr virus (EBV)-associated tumors in the setting of HIV infection. Twenty-one AIDS-related lymphomas, including five CD30-positive ALC and 11 small noncleaved cell (SNCC) lymphomas, and five Hodgkin's disease (HD) specimens were characterized regarding the immunophenogenotypic features, the frequency and subtype distribution of EBV (as defined by in situ hybridization [ISH], Southern blot, and a polymerase chain reaction [PCR] amplification of the EBV nuclear antigen-2 [EBNA-2] region) antigen expression (latent membrane protein-1 [LMP-1], EBNA-2, and for alterations of the tumor suppressor gene p53. Combined immunophenotypic and immunogenotypic analyses showed a derivation from anomalously matured B cells in four of five CD30-positive ALC lymphomas, whereas SNCC showed features of mature B cells; no evidence of immunoglobulin or TCR gene rearrangement could be obtained in HD cases. Combined ISH and Southern blot analyses revealed that EBV was more strictly associated with HD (five of five) and CD30-positive ALC lymphomas (four of five) than with SNCC lymphomas (four of 11). EBV-positive samples from CD30-positive ALC lymphomas carried type 1 EBV (two of two specimens tested), whereas both EBV subtypes were observed in SNCC lymphomas and HD samples. All three forms of viral latent gene expression were found in the EBV positive CD30-positive ALC lymphomas. SNCC specimens did not express LMP-1 or EBNA-2, whereas HD specimens expressed LMP-1 (four of five tested) but no EBNA-2. Immunostaining for ZEBRA was consistently negative. HHV-6 DNA sequences were detected by PCR in one SNCC of the 19 specimens analyzed. Three out of five CD30-positive ALC lymphoma specimens and six of 10 SNCC showed nuclear staining for p53. No mutation was detected in any of the three CD30-positive Alc lymphoma analyzed, whereas an aberrant SSCP pattern was found in all the four SNCC samples tested. At variance with SNCC lymphomas, AIDS-related B-cell CD30- positive ALC lymphomas are strictly associated with EBV infection and may also express the broad lymphoblastoid cell line-like (LMP-1-positive, EBNA-2-positive) pattern, and lack p53 genetic lesions. Unlike EBV, HHV-6 probably does not represent a relevant factor involved in the pathogenesis of CD30-positive ALC and other HIV related lymphomas.
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PMID:Immunophenotypic and molecular analyses of acquired immune deficiency syndrome-related and Epstein-Barr virus-associated lymphomas: a comparative study. 861 54

JC virus (JCV), the agent of progressive multifocal leukoencephalopathy (PML), has been shown by both immunohistochemistry and flow cytometry to be associated with p53 protein stabilization. Since stabilization/inactivation of p53 is associated with the development of genomic instability, abnormal cell DNA contents are to be expected in JCV-infected cells of PML. This work explores that possibility by image analysis evaluation of DNA content in PML-infected oligodendrocytes and bizarre astrocytes. Brain paraffin sections of PML lesions from five adult male patients with the acquired immune deficiency syndrome (AIDS) were treated with the Feulgen technique to obtain a stochiometric staining of DNA and analyzed with a microscope image processor. Inclusion-bearing oligodendrocytes exhibited near tetraploid DNA indices in each of the five cases, whereas atypical astrocytes were in the hypertetraploid range in all cases and were polyploid in four instances. This evidence of DNA amplification in PML glial cells is congruent with the functional abolition of p53 protein in association with JCV infection and lends further support to the role of p53 as a keeper of diploid status and guardian of genomic stability.
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PMID:DNA amplification in glial cells of progressive multifocal leukoencephalopathy: an image analysis study. 864 99


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