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

Identification of inherited cancer-predisposing genes offers opportunities for cancer prevention. Inherited susceptibility genes have been identified, primarily through studies of unusual cancer cases and families but also through general population studies. Examples include the RB1 gene for retinoblastoma; the WT1 gene for Wilms' tumor; germline p53 mutations in families with the Li-Fraumeni syndrome; the NF1 and NF2 genes for neuroblastomatosis, types 1 and 2; the VHL gene for renal cancer and other tumors associated with Von Hippel-Lindau disease; the APC gene for adenomatous polyposis coli; the BRCA1 gene for hereditary breast and ovarian cancer; and the mismatch repair genes for colon and other common cancers. For some cancers, identification of gene carriers might be beneficial for targeting screening and chemopreventive interventions. On the other hand, predisposition testing for cancer has the potential for harm from loss of insurability and employability, psychological distress, social stigmatization and other adverse effects. Research is needed to identify predisposition testing procedures that maximize benefits while minimizing harm to subjects. Chemoprevention trials in genetically susceptible populations offer the prospect of finding effective methods of reducing future cancer risk.
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PMID:Identification and management of inherited cancer susceptibility. 874 2

A novel transcription factor binding element in the human p53 gene promoter has been characterized. It lies about 100 bp upstream of the major reported start site for human p53 gene transcription. On the basis of DNase I footprinting studies, electromobility shift assay patterns, sequence specificity of binding, the binding pattern of purified transcription factors, effects of specific antibodies, and methylation interference analysis we have identified the site as a composite element which can bind both YY1 and NF1 in an independent and mutually exclusive manner. The site is conserved in the human, rat, and mouse p53 promoters. The occupancy of the site varies in a tissue-specific manner. It binds principally YY1 in nuclear extracts of rat testis and spleen and NF1 in extracts of liver and prostate. This may facilitate tissue-specific control of p53 gene expression. When HeLa cells were transiently transfected with human p53 promoter-chloramphenicol acetyltransferase reporter constructs, a mutation in this composite element which disabled YY1 and NF1 binding caused a mean 64% reduction in basal p53 promoter activity. From mutations which selectively impaired YY1 or NF1 binding and the overexpression of YY1 or NF1 in HeLa cells we concluded that both YY1 and NF1 function as activators when bound to this site. In transient cotransfections E1A could induce the activity of the p53 promoter to a high level; 12S E1A was threefold as efficient as 13S E1A in this activity, and YY1 bound to the composite element was shown to mediate 55% of this induction. Overexpressed YY1 was shown to be able to synergistically activate the p53 promoter with E1A when not specifically bound to DNA. Deletion of an N-terminal domain of E1A, known to be required for direct E1A-YY1 interaction and E1A effects mediated through transcriptional activator p300, blocked the E1A induction of p53 promoter activity.
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PMID:YY1 and NF1 both activate the human p53 promoter by alternatively binding to a composite element, and YY1 and E1A cooperate to amplify p53 promoter activity. 881 7

To investigate the molecular mechanisms of tuberous sclerosis (TSC) histopathologic lesions, we have tested for loss of heterozygosity the two TSC loci (TSC1 and TSC2) and seven tumor suppressor gene-containing regions (TP53, NF1, NF2, BRCA1, APC, VHL, and MLM) in 20 hamartomas from 18 TSC patients. Overall, eight angiomyolipomas, eight giant cell astrocytomas, one cortical tuber, and three rhabdomyomas were analyzed. Loss of heterozygosity at either TSC locus was found in a large fraction of the informative patients, both sporadic (7/14) and familial (1/4). Interestingly, a statistically significant preponderance of loss of heterozygosity at TSC2 was observed in the sporadic group (P < 0.01). Among the possible explanations considered, the bias in the selection for TSC patients with the most severe organ impairment seems particularly appealing. According to this view, a TSC2 defect might confer a greater risk for early kidney failure or, possibly, a more rapid growth of a giant cell astrocytoma. None of the seven antioncogenes tested showed loss of heterozygosity, indicating that the loss of either TSC gene product may be sufficient to promote hamartomatous cell growth. Finally, the observation of loss of heterozygosity at different markers in an astrocytoma and in an angiomyolipoma from the same patient might suggest the multifocal origin of the second-hit mutation.
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PMID:Apparent preferential loss of heterozygosity at TSC2 over TSC1 chromosomal region in tuberous sclerosis hamartomas. 882 21

Research on Neurofibromatosis (NF) has been directed at understanding what determines disease quiescence, exacerbation, and the possible malignant evolution. Studies on NF have examined the role of genetic oncosuppression in the evolution of the defence against the non-self. Paraffin fixed specimens of benign and malignant neoplasia, occurring in patients with NF1 and NF2, were tested for the presence of p53: a reliable marker of genetic oncosupression. The wild type variant of p53 is expressed in malignant neoplasia, and is usually not expressed in benign tumors. Contrariwise, an immune reaction it is seen in benign tumors and is practically absent in malignant tumors. Evidence of protein p53 in the various malignant neoplasias studied by our group seems to reflect the up-regulation on the oncosuppresive genetic potential that occurs while there is a lack of immunological defence. In the presence of an immunological defence, the expression p53 is normally not seen e.g. plexiform neurofibromas. The evolution of the various neoplastic types here reported was the same as that reported by current clinical and experimental models: the cell's defective genes are no longer suppressed and after activation the genes undergo initiation, promotion, and the cell sustains inflammatory-immune reactions that lead to fibrosis; what follows is a variable period of apparent quiescence. Severe pathogenic stimuli may act on predisposed cells and deteriorate pre-existing genetic damage, casting the cell into a phase of dysplastic or neoplastic proliferation that overcomes the body's defences. Hope for future therapy lies in the development of drugs that can either mimic the immune system or the proteins encoded by the oncosuppressor genes.
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PMID:Tumour suppressor genes, immunology and local manifestations of neurofibromatosis phenotypes. 900 79

Interspecific hybrid backcross animals from a Bos taurus x Bos gaurus F1 female were used to construct a linkage map of bovine Chromosome (Chr) 19. This map includes eight previously unmapped type I anchor loci, CHRNB1, CRYB1, GH1, MYL4, NF1, P4HB, THRA1, TP53, and five microsatellite markers, HEL10, BP20, MAP2C, ETH3, BMC1013, from existing linkage maps. The linkage relationship was determined to be centromere-HEL10-18.8cM-NF1-4.0cM-CRYB1-11 .2cM-(BP20, CHRNB1, TP53)-4.0cM-(MAP2C, GH1, MYL4, THRA1)-14.4cM-P4HB-11.2cM-ETH3-4. 0cM-BMC1013. It was previously revealed that bovine Chr 19 contains the largest known conserved autosomal synteny among human, bovine, and mouse. This study has shown that gene orders within this segment are not conserved among the three species. We propose structural changes in an ancestral mammalian chromosome to account for these differences. This is the first interspecific hybrid backcross used in bovine linkage studies, and it has proven to be an effective tool for incorporating bovine type I loci into the linkage map even with the small sample size presently available. This resource will facilitate the generation of comparative linkage maps that address gene order and effectively predict the locations of unmapped loci across species.
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PMID:Construction of a bovine chromosome 19 linkage map with an interspecies hybrid backcross. 909 7

We performed longitudinal analyses of chromosomes and studied the configuration of NRAS, TP53, NF1, and cFMS genes in 70 patients with myelodysplastic syndrome(MDS). The NRAS mutations were detected in 6 patients(9%) at codons 12 or 13. The TP53 mutations were found in 10 patients(14%) in exons 4 through 8. Longitudinal studies revealed that the NRAS mutation was a late-appearing event, while the TP53 mutations were detectable at the presentation of MDS. No patients had both NRAS and TP53 mutations, simultaneously. NF1 and cFMS genes showed any mutational event among these 70 patients. Patients with a TP53 mutation had a significantly shorter survival time than those with an NRAS mutation or those without NRAS or TP53 mutation. However, patients who showed an NRAS mutation had a shorter survival time once the mutation emerged, similar to that of patients with a TP53 mutation.
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PMID:Genetic aberrations in the development and subsequent progression of myelodysplastic syndrome. 920 48

To prognosticate the implications of various allelic losses on chromosome 17 in the morphology and biology of astrocytic tumors, we have examined loss of heterozygosity (LOH) at 14 microsatellite loci on chromosome 17 in a series of 19 astrocytic tumors (3 astrocytomas, 5 anaplastic astrocytomas, and 11 glioblastomas). The DNA samples extracted from tumor and matched normal brain tissue were amplified by polymerase chain reaction (PCR) followed by polyacrylamide gel electrophoresis and photography under UV transillumination. The molecular genetic data were compared with immunohistochemistry performed with antibodies to glial fibrillary acidic protein (GFAP), MIB-1 and p53 protein. LOH was observed in 11/19 (58%) instances with frequent involvement of TP53, NF1, and D17S795 loci, LOH at D17S578 and D17S520 occurred in recurrent tumors exclusively. Allelic status of D17S795 in all 12 informative instances were concordant with GFAP immunoreactivity (p < 0.01, Fisher's test). p53 immunopositivity (> 25% of tumor cell nuclei) was seen in 11 (58%) tumors, of which 6 were informative of TP53 locus with 2 (33%) demonstrating LOH. The MIB-1 staining indexes in astrocytomas, anaplastic astrocytomas, and glioblastomas were 1.9 +/- 0.9, 8.4 +/- 4.0, and 17.1 +/- 7.1% (mean +/- SD), respectively, and their differences were statistically significant (p < 0.05, Student's t test). A trend of inverse relationship between patient survival and the number of tumor cell nuclei with immunohistochemically detectable p53 protein was seen in glioblastoma cases: 20.5 +/- 12.7 versus 13.7 +/- 6.3 months (mean +/- SD) in instances with > or > or = 25% positive cells, respectively. We conclude, the intriguing correlation between allelic status of D17S795 microsatellite locus and GFAP immunoreactivity suggests the possible involvement of q21.2 segment of chromosome 17 in the morphology and biology of astrocytic tumors.
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PMID:Chromosome 17 allelic loss in astrocytic tumors and its clinico-pathologic implications. 926 49

Recent knowledge about biological role of tumor suppressor genes and their products: RB1, p53, WT1, DCC, APC/FAP, NF1, NF2, VHL, MCC and MTS1 is presented. The main approaches of these agents as physiological regulators of cell growth and proliferation are discussed. Views on the tumor suppressor genes involvement in the development of inherited and sporadic forms of cancer have been reviewed.
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PMID:[Antioncogenes--tumor suppression genes]. 933 80

Few genes have a proven role in the pathogenesis of myelodysplastic syndromes (MDS). The most common abnormalities involve the RAS genes, most notably the N-RAS gene, and are present in 10% of cases at diagnosis and in 30% to 40% during the course of the disease. Mutations of the p53 are found in 5% to 10% of cases. Mutations of the cFMS genes are less common, abnormalities of the NF1 genes seem to occur only in children, and abnormalities of the RB genes are exceedingly rare. A few instances of t(5;12) or t(3;21) translocation have been demonstrated, and their study has provided evidence that the TEL, EVI1, MDS1, and AML1 genes are involved in some cases of MDS. The presence in MDS of recurrent chromosome 7, 5q, and 20q deletions suggests that these chromosomal segments may bear tumor suppressor genes involved in MDS. The gene(s) involved remain(s) to be identified. Clonality studies have shown that stem cell involvement usually occurs at the myeloid level and that normal multipotent stem cells persist in many patients with MDS. This opens up the promising possibility that transplantation of autologous multipotent stem cells may be an effective therapeutic approach.
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PMID:[Molecular abnormalities and clonality in myelodysplastic syndromes]. 940 79

A bovine bacterial artificial chromosome (BAC) library was screened for the presence of eight type I anchor loci previously used within hybrid somatic cells and an interspecies hybrid backcross to construct a genome map of bovine chromosome 19 (BTA19). Six out of eight loci were identified in the BAC library (NF1, CRYB1, CHRNB1, TP53, GH1 and P4HB). The BACs were then used in single-colour fluorescence in situ hybridization (FISH) to assign these genes to BTA19 band locations. Gene order was determined by single-colour FISH, and was confirmed by dual-colour FISH to mitotic and meiotic chromosomes. The order, centromere-NF1-CRYB1-CHRNB1-TP53-GH1-P4HB, was in agreement with the order determined by linkage analyses. In addition, the order of CHRNB1 and TP53, previously unresolved by linkage analyses, was established. These data provide high-resolution cytogenetic anchorage of the BTA19 genome map from chromosome bands 14-22.
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PMID:Physical assignment of six type I anchor loci to bovine chromosome 19 by fluorescence in situ hybridization. 969 73


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