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 background frequency of mutations in human tissues is an important issue in cancer susceptibility and genotoxic exposure determinations. Here we report the detection of rare mutant leukocytes containing oncogenic base substitutions of the Harvey-ras, N-ras, and p53 genes by the Needle-in-a-Haystack mutation assay with a sensitivity of one cell in a million. Altogether, we detected and identified 17 independent mutations of 66 separate base site analyses of peripheral blood specimens obtained from 19 apparently normal individuals. Two individuals harbored a substantially increased frequency of mutant cells, representing 9 of the 17 independent mutations found. These results suggest that up to 1 in 10 normal individuals may harbor a significant frequency of oncogenic mutations in circulating leukocytes.
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PMID:Oncogenic base substitution mutations in circulating leukocytes of normal individuals. 1076 67

In humans, the inheritance of mutations in the breast cancer susceptibility genes BRCA1 and BRCA2 increases the risk of developing breast and ovarian cancer. To study their biological function and to create animal models for these cancer susceptibility genes, several strains of mice mutated in the homologous genes Brca1 and Brca2 have been generated by gene targeting. Analyses of these "knock-out" mouse mutants have provided invaluable knowledge about the function of these genes. Brca1 and Brca2 null mutants are similar in phenotype: mutations in both genes result in embryonic lethality and the developing embryos show signs of a cellular proliferation defect associated with activation of the p53 pathway. The significance of this activation, as well as the role of these cancer susceptibility genes in DNA damage repair, is discussed.
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PMID:Developmental studies of Brca1 and Brca2 knock-out mice. 1081 37

Germ-line p53 point mutations have been reported for various families with Li-Fraumeni syndrome (LFS) characterized by a dominantly inherited increased susceptibility for the development of early age of onset neoplasms of diverse origin in multiple family members. Recently Bell et al reported that mutations in a known checkpoint gene called Chk2 cause some cases of LFS. This review will present the effective interaction of epidemiologic method and molecular genetics on the identification of cancer predisposition and will discuss about various problems of predictive testing for inherited mutations in cancer susceptibility genes.
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PMID:[Li-Fraumeni syndrome]. 1092 21

Immune surveillance by cytotoxic lymphocytes against cancer has been postulated for decades, but direct evidence for the role of cytotoxic lymphocytes in protecting against spontaneous malignancy has been lacking. As the rejection of many experimental cancers by cytotoxic T lymphocytes and natural killer cells is dependent on the pore-forming protein perforin (pfp), we examined pfp-deficient mice for increased cancer susceptibility. Here we show that pfp-deficient mice have a high incidence of malignancy in distinct lymphoid cell lineages (T, B, NKT), indicating a specific requirement for pfp in protection against lymphomagenesis. The susceptibility to lymphoma was accentuated by simultaneous lack of expression of the p53 gene, mutations in which also commonly predispose to human malignancies, including lymphoma. In contrast, the incidence and age of onset of sarcoma was unaffected in p53-deficient mice. Pfp-deficient mice were at least 1,000-fold more susceptible to these lymphomas when transplanted, compared with immunocompetent mice in which tumor rejection was controlled by CD8(+) T lymphocytes. This study is the first that implicates direct cytotoxicity by lymphocytes in regulating lymphomagenesis.
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PMID:Perforin-mediated cytotoxicity is critical for surveillance of spontaneous lymphoma. 1097 40

The purpose of this study was to establish the frequencies of CYP2D6, CYP1A1, GSTM1 and p53 polymorphic genotypes in Tundra Nentsi, which comprises the small group of indigenous people belonging to Northern Mongoloids and Caucasians of Western Siberia. A total number of 102 Tundra Nentsi individuals and 96 Caucasians of Western Siberia were genotyped by means of polymerase chain reaction-based assays. Mutated alleles comprising CYP2D6*4, CYP1A1Val, GSTM1*0 and p53Pro were analysed along with the wild-type alleles. The results showed the intermedial position of CYP2D6*4 allele frequency in Tundra Nentsi, compared to Caucasians and Orientals (0.07 versus 0.2, P = 0.0003; 0.07 versus 0.003, P = 1 x 10(-6), respectively). Thus, our data indicate that the intermedial position of Tundra Nentsi between Orientals and Caucasians most likely shows the Caucasian ancestral origin of CYP2D6*4 allele. Comparative analysis of p53Pro allele frequency showed the pronounced ethnic differences with geographic gradient. Though the frequency of p53Pro allele ranged from 0.17 in Tundra Nentsi up to 0.3 in Caucasians of Western Siberia (P = 0.002), which is in agreement with the previously reported radial distribution of the known genetic markers. No differences were found in the CYP1A1Val allele distribution among Caucasians of Western Siberia and Caucasoid populations presented in other studies, whereas the frequency of Val allele in Nentsi was 1.5-fold higher (P = 0.076) compared to the Japanese group. It was found that the frequency of GSTM1 null genotype in Tundra Nentsi was only 39.8%. The frequency of GSTM1 null genotype in females was higher than in males (0.27 and 0.50, respectively) but that difference was not statistically significant. Comparative analyses of the distribution of putative markers towards cancer susceptibility, CYP1A1Val, GSTM1*0 and p53Pro alleles, have shown that the healthy Tundra Nentsi population (Northern Mongoloids) have a low number of p53Pro alleles and GSTM1*0/*0 genotypes and a high level of CYP1A1Val alleles. Further investigations of gene polymorphisms in isolated Northern native populations would be valuable in clarifying the origin of Northern natives. All this is important for comparative analyses of pharmacogenetic data in Mongoloid populations.
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PMID:Genetic polymorphisms of CYP2D6, CYP1A1, GSTM1 and p53 genes in a unique Siberian population of Tundra Nentsi. 1097 7

The human MDM2 oncogene, well known as the tumor suppressor gene p53's partner, plays an important role in tumorigenesis whether it is dependent on or independent of TP53. In this study, we investigated in a PCR-sequencing analysis the exon 11 of the human MDM2 gene for gene alterations. A MboII polymorphism occurs in 8% of normal blood donors (8 out of 100 probands) and in 13% of the soft tissue sarcoma patients (11 out of 82 patients). Of note was that two STS patients carried the gene alteration only in the tumor specimens heterozygously but not in normal tissue. In a Kaplan-Meier analysis, patients without the polymorphism, indicated a median survival rate of 57 months, whereas, patients with the polymorphism survived on average only 38 months. We suggest that this polymorphism might be associated with an increased cancer susceptibility.
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PMID:A MboII polymorphism in exon 11 of the human MDM2 gene occuring in normal blood donors and in soft tissue sarcoma patients: an indication for an increased cancer susceptibility? 1108 94

Ataxia-telangiectasia (AT) is an autosomally recessive human genetic disease with pleiotropic defects such as neurological degeneration, immunodeficiency, chromosomal instability, cancer susceptibility and premature aging. Cells derived from AT patients and ataxia-telangiectasia mutated (ATM)-deficient mice show slow growth in culture and premature senescence. ATM, which belongs to the PI3 kinase family along with DNA-PK, plays a major role in signaling the p53 response to DNA strand breaks. Telomere maintenance is perturbed in yeast strains lacking genes homologous to ATM and cells from patients with AT have short telomeres. We examined the length of individual telomeres in cells from ATM(-/-) mice by fluorescence in situ hybridization. Telomeres were extensively shortened in multiple tissues of ATM(-/-) mice. More than the expected number of telomere signals was observed in interphase nuclei of ATM(-/-) mouse fibroblasts. Signals corresponding to 5-25 kb of telomeric DNA that were not associated with chromosomes were also noticed in ATM(-/-) metaphase spreads. Extrachromosomal telomeric DNA was also detected in fibroblasts from AT patients and may represent fragmented telomeres or by-products of defective replication of telomeric DNA. These results suggest a role of ATM in telomere maintenance and replication, which may contribute to the poor growth of ATM(-/-) cells and increased tumor incidence in both AT patients and ATM(-/-) mice.
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PMID:Extra-chromosomal telomeric DNA in cells from Atm(-/-) mice and patients with ataxia-telangiectasia. 1118 76

Gene therapy is a therapeutic approach that is designed to correct specific molecular defects that contribute to the cause or progression of cancer. Genes that are mutated or deleted in cancers include the cancer susceptibility genes p53 and BRCA1. Because mutational inactivation of gene function is specific to tumor cells in these settings, cancer gene correction strategies may provide an opportunity for selective targeting without significant toxicity for normal nontumor cells. Both p53 and BRCA1 appear to inhibit cancer cells that lack mutations in these genes, suggesting that the so-called gene correction strategies may have broader potential than initially believed. Increasing knowledge of cancer genetics has identified these and other genes as potential targets for gene replacement therapy. Initial patient trials of p53 and BRCA1 gene therapy have provided some indications of potential efficacy, but have also identified areas of basic and clinical research that are needed before these approaches may be widely used in patient care.
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PMID:Gene therapy for carcinoma of the breast: Therapeutic genetic correction strategies. 1125 Jun 90

The recognition that prostate cancer clusters within families has led to the search for prostate cancer susceptibility genes. Recently, the HPC2/ELAC2 gene on chromosome 17p has been identified as a potential prostate cancer predisposition gene using both family based as well as case-control studies. Many cancer susceptibility genes act as tumor suppressor genes in which inactivation of one allele in the tumor can be detected via loss of heterozygosity (LOH). To determine whether the HPC2/ELAC2 gene demonstrates significant LOH in sporadic and familial prostate cancers, paired tumor and normal DNA samples were isolated using microdissection techniques from 44 radical prostatectomy specimens. Cases were analyzed using a panel of markers in the following order: TP53-D17S969-D17S947-(HPC2/ELAC2)-D17S799-D17S936. LOH was observed in < 10% of cases using the four markers that map to the HPC2/ELAC2 region. However, allelic loss was observed at the TP53 gene in 25% of informative cases. Taken together, inactivation of the HPC2/ELAC2 gene via LOH is a relatively uncommon event in prostate cancer. Future studies will determine whether 17p LOH occurs in the subset of patients with an inherited mutation in HPC2/ELAC2.
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PMID:Loss of heterozygosity of the putative prostate cancer susceptibility gene HPC2/ELAC2 is uncommon in sporadic and familial prostate cancer. 1175 79

Mutations in several DExH-containing DNA helicases, including XPD, XPB, WRN, and BLM, are associated with rare familial cancer syndromes characterized by genomic instability and cancer susceptibility. Known cellular activities of these helicases include DNA replication, repair, recombination, and/or transcription. The p53 tumor suppressor is a regulator of cellular responses to stress, and is biochemically involved in the induction of cell-cycle arrest, apoptosis and DNA repair, all of which contribute to maintenance of genomic integrity. Physical and functional interactions of p53 with DExH-containing DNA helicases have been described. We propose that such interactions could be compromised in inherited disorders and contribute to their cancer susceptibility. In particular, the role of DNA helicases in p53-mediated apoptotic pathways is reviewed.
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PMID:p53-mediated apoptosis and genomic instability diseases. 1176 63


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