Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019829 (Hodgkin's disease)
 30,247 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Immunohistochemically detectable p53 protein expression is common in the Reed-Sternberg and Hodgkin's (RS-H) cells of Hodgkin's disease, but p53 gene mutations have only rarely been identified. The authors found p53 expression in RS-H cells in 16 of 30 cases of Hodgkin's disease (53%), with the percentage of RS-H positive cells ranging from 4% to 85%. In 12 of 30 cases (40%), at least 10% of the RS-H cells were positive for p53. p53 gene mutations were detected in only two cases (7%) using a single-stranded conformational polymorphism assay with a detection sensitivity of between 1% and 5%. The cellular protein, mdm-2, which can stabilize and functionally inactivate wild-type p53 protein, was expressed in RS-H cells in most of these cases (86%). However, neither case with a p53 gene mutation expressed mdm-2 (P < .005). The two cases with p53 gene mutations had a higher mean proliferative index than cases without detectable mutations (90% versus 72%; P < .02). p53 expression in RS-H cells may be related to concurrent mdm-2 protein expression and a p53-positive, mdm-2-negative immunophenotype may be predictive of gene mutations in RS-H cells.
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PMID:P53 expression in Reed-Sternberg cells does not correlate with gene mutations in Hodgkin's disease. 898 Mar 48

Although the cause(s) of clinical drug resistance in non-Hodgkin's lymphomas (NHL) is unknown, in vitro studies suggest that abnormalities of the p53 gene, bcl-2 overexpression, and low tumor proliferation rates may increase chemotherapy resistance. We analyzed tumor tissue from 75 patients with relapsed/refractory NHL (Working Formulation A through H) for p53 mutation/overexpression (abnormality), bcl-2 expression, and tumor proliferation and correlated them with multiple clinical characteristics, response to therapy, disease-free survival, and overall survival (OS). All tumor biopsy specimens were obtained within 6 weeks of treatment with EPOCH (infusional etoposide, vincristine, and doxorubicin and bolus prednisone and cyclophosphamide) chemotherapy. Overall, 16 (21%) tumors had a p53 abnormality. Of 13 tumors with overexpression, mutations were confirmed by sequence analysis in 11, and, in 44 tumors without overexpression, 3 showed mutations. A multivariate analysis showed that tumors with a p53 abnormality were more likely to be drug resistant than tumors with normal p53 (56% v 17%; P2 = .008) and to have a shorter median progression-free survival (PFS; 2.1 v 8.2 months; P2 = .008) and OS (11.7 v 21.5 months; P2 = .038), respectively. The presence of a p53 abnormality did not correlate with any clinical characteristic, bcl-2 expression, or tumor proliferation. A significant correlation was found between low tumor proliferation and drug resistance in a univariate (P2 < .006) but not multivariate analysis. Patients with tumor proliferation of less than 80% were significantly more likely to have no response to therapy (31% v 6%) or to fail to achieve a complete response (16% v 44%) and tended to have shorter PFS and OS than did patients with higher proliferation. No significant association was found between bcl-2 expression and drug resistance, PFS or OS, although patients with intermediate-grade histologies and high bcl-2 expression tended to be drug resistant as compared with low level expressors (P2 < .065). Of interest was the finding of a significant association between high bcl-2 and low tumor proliferation (P2 = .0045). In studies that have found an association between high bcl-2 expression and short PFS, bcl-2 may have been a surrogate for low tumor proliferation. Further studies are warranted to examine this question. These results suggest that p53 mutation and low tumor proliferation, but not bcl-2, may be important causes of clinical drug resistance in NHL.
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PMID:Relationship of p53, bcl-2, and tumor proliferation to clinical drug resistance in non-Hodgkin's lymphomas. 900 64

Although inherited p53 mutations are present in all somatic cells, malignant transformation is limited to certain organs and target cells. The analysis of 475 tumors in 91 families with p53 germline mutations reported since 1990 shows that breast carcinomas are most frequent (24.0%), followed by bone sarcomas (12.6%), brain tumors (12.0%), and soft tissue sarcomas (11.6%). The sporadic counterparts of these tumors also carry a high incidence of p53 mutations, suggesting that in these tissues p53 mutations are capable of initiating the process of malignant transformation. Hematological neoplasms (acute lymphoblastic leukemia and Hodgkin's lymphoma) and adrenocortical carcinomas occurred at a frequency of 4.2 and 3.6%, respectively. One-half of the families fulfilled the diagnostic criteria of the Li-Fraumeni syndrome. There were marked organ-specific differences in the mean age at which carriers of p53 germline mutations present with neoplastic disease: 5 years for adrenocortical carcinomas, 16 years for sarcomas, 25 years for brain tumors, 37 years for breast cancer, and almost 50 years for lung cancer. Analysis of the mutational spectrum showed a predominance of G:C-->A:T transitions at CpG sites, suggesting an endogenous formation, eg, by deamination of 5-methylcytosine, rather than a causation by environmental mutagenic carcinogens. The location of mutations within the p53 gene was found to be similar to that of somatic mutations in sporadic tumors. There is no evidence of an organ or target cell specificity of p53 germline mutations; the occasional familial clustering of certain tumor types is more likely to reflect the genetic background of the respective kindred or the additional influence of environmental and nongenetic host factors.
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PMID:Tumors associated with p53 germline mutations: a synopsis of 91 families. 900 16

The 357 amino acid open reading frame 1 (ORF-1), also designated DR7, within the SalI-L fragment of human herpesvirus 6 (HHV-6) exhibited transactivation of the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) promoter and increased HIV-1 replication (Kashanchi et al., Virology, 201, 95-106, 1994). In the current study, the SalI-L transforming region was localized to the SalI-L-SH subfragment. Several ORFs identified in SalI-L-SH by sequence analysis were cloned into a selectable mammalian expression vector, pBK-CMV. Only pBK/ORF1 transformed NIH3T3 cells. Furthermore, cells expressing ORF-1 protein produced fibrosarcomas when injected into nude mice, whereas control cells, expressing either no ORF-1 protein or C-terminal truncated (after residue 172) ORF-1 protein, were not tumorigenic. Western blot analysis of proteins extracted from the tumors revealed ORF-1 protein. Additional studies indicated that ORF-1 was expressed in HHV-6-infected human T-cells by 18 h. Co-immunoprecipitation experiments showed that ORF-1 protein bound to tumor suppressor protein p53, and the ORF-1 binding domain on p53 was located between residues 28 and 187 of p53, overlapping with the specific DNA binding domain. Functional studies showed that p53-activated transcription was inhibited in ORF-1, but not in truncated ORF-1, expressing cells. Importantly, the truncated ORF-1 mutant also failed to cause transformation. Analysis of several human tumors by PCR revealed ORF-1 DNA sequences in some angioimmunoblastic lymphadenopathies, Hodgkin's and non-Hodgkin's lymphomas and glioblastomas. The detection of ORF-1 sequences in human tumors, while not proof per se, is a prerequisite for establishing its role in tumor development. Taken together, the results demonstrate that ORF-1 is an HHV-6 oncogene that binds to and affects p53. The identification of both transforming and transactivating activities within ORF-1 is a characteristic of other viral oncogenes and is the first reported for HHV-6.
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PMID:Human herpesvirus 6 (HHV-6) ORF-1 transactivating gene exhibits malignant transforming activity and its protein binds to p53. 901 22

Sixty-four cases of mantle cell (centrocytic) non-Hodgkin's lymphomas have been analyzed for their cytomorphologic features, proliferation indices, bcl-1 rearrangements, p53 expression patterns, and DNA content by both interphase cytogenetic and DNA flow cytometric analyses. According to cytomorphology, three subtypes were recognized: a common, a lymphoblastoid, and a pleomorphic variant of mantle cell lymphoma (MCL). Blastoid MCL subtypes were characterized by distinctly elevated mitotic counts (57 and 51/10 HPF v 21/10 high-power fields in common MCL), proliferation indices (58% and 53% v 27% in common types, respectively; P < .001), frequent bcl-1 rearrangements at the major translocation cluster locus (59% v 40%), and overexpression of p53 (21% v 6%). However, the most interesting finding was a striking tendency of blastoid MCL subtypes to harbor chromosome numbers in the tetraploid range (36% of lymphoblastoid and 80% of pleomorphic types v 8% of common variants, P < .001), a feature clearly separating these neoplasms from other types of B-cell non-Hodgkin's lymphoma and possibly being related to cyclin D1 overexpression. Our data indicate that, although characterized by a uniform immunophenotype and common biologic background, MCL shows a broad spectrum of morphologic features ranging from small cell to blastoid types and that the morphologic spectrum is mirrored by distinct biologic features.
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PMID:Blastoid variants of mantle cell lymphoma: frequent bcl-1 rearrangements at the major translocation cluster region and tetraploid chromosome clones. 902 66

The incidence of non-Hodgkin's lymphoma is greatly increased in human immunodeficiency virus (HIV)-infected individuals. Most are clinically aggressive B-cell lymphomas exhibiting Burkitt-type, immunoblastic or large-cell morphology. Approximately 80% arise systemically (nodal or extranodal), and the remaining 20% arise in the central nervous system. A small proportion are body cavity-based (primary effusion) lymphomas associated with Kaposi's sarcoma-associated herpesvirus (KSHV) infection. Possible factors contributing to lymphoma development include HIV-induced immunosuppression, chronic antigenic stimulation, and cytokine overproduction. These phenomena are associated with the development of oligoclonal B-cell expansions. The appearance of malignant lymphoma is characterized by the presence of a monoclonal B-cell population displaying a variety of genetic lesions including Epstein-Barr virus (EBV) infections, c-myc gene rearrangement, bcl-6 gene rearrangement, ras gene mutations, and p53 gene mutations/deletions. The number and type of genetic lesions varies according to anatomic site of origin and histopathology. In the case of Burkitt-type lymphoma, virtually 100% exhibit c-myc gene rearrangement, two thirds display p53 gene mutations, one third contain EBV, and none exhibit bcl-6 gene rearrangements. In contrast, in the case of immunoblastic lymphoma, virtually 100% contain EBV, 25% display c-myc gene rearrangements, 20% display bcl-6 gene rearrangements, and few exhibit p53 gene mutations. These findings suggest that more than one pathogenetic mechanism is operational in the development and progression of acquired immunodeficiency syndrome (AIDS)-related lymphoma. Further work is necessary to develop a thorough understanding of the origin and pathogenesis of malignant lymphoma in the setting of HIV infection. AIDS-related lymphoma remains an important biologic model for investigating the development and progression of high-grade non-Hodgkin lymphomas as well as malignant lymphomas that develop in immune-deficient hosts.
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PMID:Molecular pathology of acquired immunodeficiency syndrome-related non-Hodgkin's lymphoma. 904 11

To elucidate the role of cell turnover in primary gastric B-cell non-Hodgkin's lymphomas we studied tissue samples of 72 patients-26 small cell (25 MALT lymphomas) and 46 large cell (31 MALT lymphomas). Proliferation indices and apoptotic indices were measured by Mib-1 expression and terminal deoxynucleotidyltransferase (TdT)-mediated nick end labelling, respectively. Furthermore, expression of the apoptosis related gene-products bcl-2 and p53 was studied. Large cell lymphomas showed significantly higher proliferation indices (59.1% vs. 15.4%) and apoptotic indices (3.2% vs.0.7%) than small cell lymphomas. Proliferation and apoptotic indices were positively correlated (r = 0.371, P = 0.03). Expression of the bcl-2 protein was significantly higher in the small cell lymphomas. Furthermore, cases with a high bcl-2 expression showed both a significantly decreased proliferation (P < 0.0001) and apoptotic index (P = 0.0096) compared to bcl-2 negative cases. Expression of the mutant p53 protein was present in 8.0% of small cell and in 18.2% of large cell lymphomas. p53 positive cases showed significantly higher proliferation indices, but showed no correlation with apoptotic index. These data suggest that impaired apoptosis by bcl-2 may be more prominent than proliferation in the genesis of small cell lymphomas, whereas a high cell turnover characterizes large cell primary gastric lymphomas.
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PMID:Proliferation and apoptosis in primary gastric B-cell non-Hodgkin's lymphoma. 906 40

p53 is a tumour suppressor gene which is often found to be inactivated in most types of human cancer. p53 is a transcription factor, the inactivation of which may lead to significant variations in the levels of p53 downstream proteins, such as p21WAF1/CIP1 and MDM2. In view of the significance of p21WAF1/CIP1 and MDM2 as wild-type (wt) p53 targets, this study was undertaken to monitor the varying expression of these proteins in non-Hodgkin's lymphomas (NHLs) in relation to p53 gene status. A total of 57 cases of different histological types of NHL were included in this study. Proteins p53, p21WAF1/CIP1, and MDM2 were analysed by immunohistochemical techniques, taking the levels expressed in reactive lymphoid tissues as reference points. p53 gene point mutations (exons 5-8) were looked for using the PCR-SSCP technique and direct sequencing. Fifteen of the 57 cases studied showed 16 mutations at the p53 gene: 12 missense, one nonsense, two silent mutations, and one frameshift deletion. Most missense mutations were associated with high levels of p53 protein, while the nonsense mutations and frameshift deletion did not induce detectable levels of p53. All cases with mutation at the p53 gene (15) showed null or low levels of p21WAF1/CIP1 and MDM2 proteins, suggesting that null or missense mutations at this gene give rise to a protein that is unable to transactivate the p21WAF1/CIP1 and MDM2 genes. The association between missense p53 mutation and dissociate immunophenotype (p53+, MDM2-, p21-) was statistically significant (Fisher's exact test, P = 0.0024). This anomalous p53+, MDM2-, p21- phenotype was also found in a small group of five cases with wt p53; this could indicate that in these cases p53 transactivation capacity has been abrogated by a mechanism other than p53 mutation. Most cases with the wt p53 gene show simultaneous immunohistochemical expression of all three proteins and often display higher levels than those found in reactive lymphoid tissue. There is a tendency for EBV-positive cases to harbour high levels of p53+ and p21+, suggesting that EBV could be involved in the nuclear accumulation of p53 and p21WAF1/CIP1 in NHL.
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PMID:p21WAF1/CIP1 and MDM2 expression in non-Hodgkin's lymphoma and their relationship to p53 status: a p53+, MDM2-, p21-immunophenotype associated with missense p53 mutations. 907 3

In order to clarify the role of spontaneous apoptosis of non-Hodgkin's lymphomas in the growth regulation system, apoptotic indices (AI) assessed by DNA nick end-labeling and proliferative activity, estimated in terms of KI-67 labeling indices (KI) and mitotic indices (MI), were compared. In addition, expression of bcl-2, p53 and c-myc was also examined in relation to these indicators. For this study, 103 lymphoma cases were used, comprising 72 of B cell and 31 of T cell origin (42 nodal and 62 extranodal). AI, KI and MI were significantly increased in line with bcl-2 negativity and p53 positivity, and there was no relation to the T, B cell classification or expression of c-myc. These indicators positively correlated overall. Positive correlation was stricter in groups believed to represent a good prognostic predictive factor, such as B cell origin, bcl-2(+), p53(-) and c-myc(-). Significant cross-correlation was noted only between bcl-2 versus T, B cell classification. However, no inverse correlation between bcl-2 and p53 was evident. These results suggest, in non-Hodgkin's lymphomas, that apoptosis plays an important role together with proliferative activity in counter-balancing tumor volume, and is strictly linked to bcl-2 expression, less so to p53 expression, but independent of T, B cell classification and c-myc expression. Apoptotic indices may be a predictive indicator for prognosis similar to proliferative activity.
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PMID:Apoptosis and proliferative activity of non-Hodgkin's lymphomas: comparison with expression of bcl-2, p53 and c-myc proteins. 908 26

A large fraction of non-Hodgkin's lymphomas (NHLs) accumulate a wild-type form of the p53 tumor suppressor protein at the nuclear level. In normal cells, p53 induction is associated with a temporary cell growth arrest at the G1-S boundary of the cell cycle. This activity of p53 as a G1 checkpoint molecule is strictly dependent on its ability to induce the transcription of the inhibitor of the cyclin dependent kinase, p21. To verify the functionality of the wild-type p53 protein accumulated in NHL cells, 70 cases were comparatively analyzed for p53 and p21 expression and status of the respective genes. Overexpression of the wt p53 protein was associated with the accumulation of p21, indicating that p53 is functional with respect to p21 induction in these tumors. The coaccumulation of p53 with Ki-67 antigen indicates that wt p53-positive cells and p21-positive cells, as well, are actively proliferative elements, supporting the notion that p53-induced, p21-mediated growth arrest is somehow overridden in NHL cells. No p21 mutation or particular allele variant was shown to correlate with p21 protein accumulation, thus excluding a role for p21 structural abnormalities. Taken together, our data suggest the existence in NHL of a peculiar mechanism of functional inactivation of the p53 G1 checkpoint pathway occurring downstream of the CDK inhibitor p21.
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PMID:Human non-Hodgkin's lymphomas overexpress a wild-type form of p53 which is a functional transcriptional activator of the cyclin-dependent kinase inhibitor p21. 911 98


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