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)

The wide clinicopathologic heterogeneity of non-Hodgkin's lymphoma is reflected by the various molecular pathways underlying non-Hodgkin's lymphoma pathogenesis, including activation of dominantly acting oncogenes, deletion and inactivation of tumor-suppressor genes, viral infection, deregulation of cytokine networks, and chronic antigenic stimulation. Molecular lesions involving protooncogenes include activation of bcl-2 and bcl-1 in specific subsets of low-grade non-Hodgkin's lymphomas and c-myc in a proportion of intermediate- and high-grade non-Hodgkin's lymphomas. The deregulation of these genes promotes cell growth or protects the tumor population from programmed cell death, or both. Additional genetic abnormalities representing putative sites of novel oncogenes contributing to lymphomagenesis include chromosomal breaks at 3q27 in intermediate-grade non-Hodgkin's lymphoma and at 9p13 in small lymphocytic lymphoma. The role of inactivation of tumor-suppressor loci is best exemplified by the frequent inactivation of p53 in Burkitt's lymphoma and by the recurrent deletion of 6q25-q27 and 6q21-q23 in intermediate- and high-grade non-Hodgkin's lymphoma, respectively. Infection by Epstein-Barr virus occurs in a variable fraction of high-grade non-Hodgkin's lymphomas, whereas it is usually absent in other types of non-Hodgkin's lymphoma. Other mechanisms supporting non-Hodgkin's lymphoma growth and development include autocrine or paracrine cytokine loops, or both, and clonal expansion through antigen receptor stimulation. The heterogeneity of non-Hodgkin's lymphoma pathogenesis provides a framework for the development of novel classification methods of potential clinical relevance.
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PMID:Biologic and molecular characterization of non-Hodgkin's lymphoma. 821 89

We derived the lymphoma cell lines OCI-Ly 13.1 and OCI-Ly 13.2 from a patient with non-Hodgkin's lymphoma at the time of presentation and during chemotherapy-resistant relapse. These lines were of T-cell phenotype and contained the identical T-cell receptor beta-chain rearrangement, indicating that both lines were members of the same malignant clone. The lines differed in their growth characteristics; OCI-Ly 13.1 grew slowly and required growth factors for colony formation, whereas OCI-Ly 13.2 grew rapidly and formed colonies without addition of growth factors. To test whether or not these biologic differences were associated with specific genetic changes, we evaluated the status of the c-myc and p53 genes of both cell lines. The p53 and c-myc genes of OCI-Ly 13.1 were in germline configuration and produced normal-sized transcripts. The p53 protein expressed in OCI-Ly 13.1 was recognized by the anti-p53 monoclonal antibody, PAb240, indicating a conformation typical of p53 proteins expressed by p53 alleles containing a missense mutation. However, sequencing studies of the entire p53 coding region did not reveal any point mutations. In contrast, the cell line OCI-Ly 13.2 contained structural abnormalities of both the c-myc and p53 genes. In addition, one of the p53 alleles was lost as determined by a cDNA probe for the p53 gene (17p 13.1) and the YNZ22.1 probe (17p 13.3). These changes resulted in the absence of p53 protein and mRNA in OCI-Ly 13.2 as detected by immunoprecipitation and Northern blot analysis, respectively. They may be a reflection of disease progression and may be associated with the altered behavior of the malignant cell population within the patient and in vitro.
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PMID:Alterations of p53 and c-myc in the clonal evolution of malignant lymphoma. 828 43

B-cell high-grade lymphomas are heterogeneous in terms of histology, clinical presentation, treatment response and prognosis. As bcl-2 and p53 gene deregulations are frequently involved in several types of lymphoid malignancies, we aimed our investigation at the study of the relation between bcl-2 and p53 expression and survival probability in a group of 119 patients with B-cell high-grade lymphoma. These were obtained from the Virgen de la Salud Hospital, Toledo, Spain (73 cases), John Radcliffe Hospital, Oxford, UK (31 cases), and the Istituto Nazionale dei Tumori, Milan, Italy (15 cases). The relation between bcl-2 protein expression and survival was small, depending on the primary localisation of the tumour (in lymph node of mucosae), and lacked a significant correlation with overall survival. In contrast with this, p53 expression was related to survival probability in our series, this relation being both significant and independent of histological diagnosis. p53-positive patients showed a sudden decrease in life expectancy in the first months after diagnosis. Multivariant regression analysis confirmed that the only parameters significantly related with survival were extranodal origin, which is associated with a better prognosis, and p53 expression, which indicates a poor prognosis. Simultaneous expression of bcl-2 and p53 was associated with a poorer prognosis than p53 alone. This is particularly significant for large B-cell lymphomas presenting in lymph nodes. The cumulative poor effect of both p53 and bcl-2 in large B-cell lymphomas, which is more significant in nodal tumours, could confirm the existence of a multistep genetic deregulation in non-Hodgkin's lymphoma. This indicates that the genetic mechanisms controlling apoptosis and their disregulation are critical steps in the progression of lymphomas.
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PMID:p53 and bcl-2 expression in high-grade B-cell lymphomas: correlation with survival time. 829 31

We analysed diagnostic phase plasma levels of thymidine kinase (TK) and mutated p53 in 81 patients with malignant lymphoma. Forty-three (53%) patients had increased (> 10 U/l) TK activity whereas 30 (37%) were positive for the mutated p53 gene product. In general, patients with p53 mutation positive tumors tended to have higher TK activity than those without. Furthermore, patients with high-grade non-Hodgkin's lymphoma (NHL) showed almost a linear correlation (rs = 0.79) between plasma levels of mutated p53 and TK. We conclude that the monoclonal antibody assisted detection of mutated p53 gene product may prove a useful adjunct to the diagnostic procedures of malignant lymphomas.
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PMID:Evaluation of plasma levels of thymidine kinase and mutated p53 in 81 patients with newly diagnosed malignant lymphoma. 830 26

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

We have investigated the immunohistochemical expression of p53 protein in 96 cases of non-Hodgkin's lymphoma using a panel of five antibodies. Positive neoplastic cells were found in 30 (31.2%) cases, which could be divided into two groups according to their patterns of reactivity with the different antibodies; i.e. those positive with both polyclonal and monoclonal antibodies, and those which were stained only by monoclonal antibodies PAb1801 and/or PAb240. Positivity was nuclear in all but six cases in which cytoplasmic staining was found. In view of the hypothesis recently raised that p53 protein induces apoptosis we have compared our results with parallel staining for bcl-2 protein since bcl-2 is believed to be important, at least in lymphomas, in suppression of apoptosis. Staining for bcl-2 protein was performed on 83 cases and it was shown that p53-positive cases accounted for 10 out of 17 (59%) of the bcl-2-negative lymphomas but only for 15 out of the 66 (23%) bcl-2-positive cases, suggesting a possible relationship between the expression of these two proteins. Thus, our data show that p53 protein is abnormally expressed in a substantial proportion of non-Hodgkin's lymphomas and bears a significant inverse relationship to bcl-2 protein expression. However the molecular basis of this expression remains to be elucidated.
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PMID:Immunohistochemical detection of p53 and bcl-2 proteins in non-Hodgkin's lymphoma. 843 40

Fourteen Non-Hodgkin's lymphoma cell lines were generated and assessed for the presence of structural p53, c-myc and bcl-2 gene changes. Single or multiple changes were observed in 11 of the lines. Alterations of the p53 gene were most frequent and documented for 10 lines by immunoprecipitation using the antibodies PAb 240 and PAb 1801, sequencing studies and Southern blot analysis. A detailed study was performed in one of the cell lines (OCI-Ly 4) for which material of the original tumor sample was available. Two point mutations identified by sequencing cDNA derived from the cell line were also present in the original tumor specimen. In contrast, DNA prepared from fibroblasts of the same patient did not show the mutations. Six of the 14 lines demonstrated c-myc rearrangements, while bcl-2 changes were observed in 4. The presence of c-myc was associated with shorter survival of this group of patients with aggressive disease. None of the other changes present as single or composite alterations were correlated with clinical outcome measures.
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PMID:p53 mutations, c-myc and bcl-2 rearrangements in human non-Hodgkin's lymphoma cell lines. 857 64

Mutations in the p53 tumor suppressor gene occur with a frequency of 12.5% in lymphoid malignancies. The viral-associated diseases, Adult T-cell Leukemia (ATL) and Burkitt's lymphoma, showed higher p53 mutation frequencies of 24% and 41%, respectively. Mutations occurred in the highly conserved regions of the p53 gene. Two new hot spots for mutation were noted in exon 7 at codons 239 and 245. The spectrum of p53 mutations differs among different cancers. Transition mutations occurring in colon and brain tumors also predominated in the majority of the lymphoid malignancies. However, B-cell chronic lymphocytic leukemia (B-CLL) and non-Hodgkin's lymphoma (NHL) had an unusually high frequency of G to T transversions. Among carcinomas of the lung, liver, breast and esophagus there is also a high frequency of G to T transversions. The differences in mutation spectra between different lymphoid diseases may be due to differences in mutagenic factors or differences in the biological properties of the p53 protein in different lymphoid compartments. Mutation of the p53 gene is associated with advanced stage of lymphoid disease and poor prognosis. For B-CLL disease, p53 mutations are associated with drug resistance. Overexpression of the bcl-2 protein is also associated with a block in apoptosis. Resistance to apoptosis could be a general mechanism for drug resistance in B-CLL and other lymphoid diseases.
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PMID:P53 gene mutations in lymphoid diseases and their possible relevance to drug resistance. 858 Jul 89

Although p53 mutations have been described frequently in high-grade B-cell non-Hodgkin's lymphoma (NHL), they have only been reported occasionally in low-grade NHL. We therefore describe clincobiologic and molecular genetic findings in two patients with p53 mutations and leukemic mantle cell lymphoma featuring an unusually aggressive course. Circulating malignant cells showed irregularity of nuclear outline with frequent deep clefts in both cases. Immunologic studies of neoplastic cells from peripheral blood samples and from cells obtained from an involved lymph node showed a mantle B-cell phenotype (CD5+, CD19+, CD22+, CD23- or weakly+ and bright expression for surface immunoglobulins). Malignant cells were shown to be hyperdiploid by cytofluorimetric study of DNA content and the presence of the t(11;14)(q13q32) was documented in one case. An altered electrophoretic mobility of p53 exon 5 was seen in both cases, with a missense mutation at codon 158 present in one case and a CAG to TAG mutation resulting in a 167-stop codon present in the second case. The percent of reactive cells with the 1801 monoclonal antibody detecting an epitope of the p53 was 37% in one case and 1% in the second case, supporting the notion that immunologic overexpression cannot be used for a selection criterion for the detection of p53 mutations. From these findings and from data available in the literature the conclusion can be drawn that p53 gene mutations at codons 158 and 167 may be associated with lymphoproliferative disorders and that low- or intermediate-grade NHL, including leukemic mantle cell lymphoma, may frequently carry this genetic change.
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PMID:p53 exon 5 mutations in two cases of leukemic mantle cell lymphoma. 860 36


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