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

Germline mutations of the p53 gene lead to cell transformation in various tissues. Such a complex cancer phenotype makes it difficult to recognize the carriers of the defective allele. Several studies undertaken to identify high-risk groups found germline p53 mutations in familial cancer aggregations and in patients with multiple tumors. We screened 189 pediatric and 48 adult patients. The high-risk groups comprised 41 patients with a family history of cancer and 35 with multiple neoplasms. Furthermore, 124 tumors were screened for somatic mutations. p53 exons 2 to 11 were analyzed by polymerase chain reaction and single strand conformation polymorphism (PCR-SSCP) followed by direct sequencing of abnormal DNA fragments. No germline p53 mutations were found and somatic mutations were detected in 5 of 59 sarcomas, globally, in 8 of 124 tumors. In conclusion, in Poland, p53 alterations do not seem very important for the predisposition to malignancy and development of sarcomas.
 ...
PMID:Screening for germline p53 mutations in pediatric and adult patients of high-risk groups in Poland. 1105 49

The familial cancer syndrome, von Hippel-Lindau (VHL) disease, characterized by a predisposition to renal cell carcinoma and certain other tumor types, is caused by mutational inactivation of the VHL tumor suppressor gene. Loss of VHL gene function is detected also in the vast majority of sporadic renal cell carcinomas. Previous reports have determined a protective role for VHL in response to serum withdrawal and glucose deprivation. In this study, the effect of UV irradiation on VHL-negative and VHL-positive renal carcinoma cells was examined. VHL-negative 786-O renal carcinoma cells underwent apoptosis following UV irradiation. In contrast, reintroduction of wild-type VHL expression protected 786-O cells from UV-mediated cell death. p53 and Bax levels were equivalent in VHL-negative and VHL-positive 786-O cells. Strikingly, cyclin-dependent kinase inhibitors p21 and p27 underwent proteasome-dependent degradation in VHL-negative 786-O cells following UV treatment. However, p21 and p27 protein levels were stable in VHL-positive cells. Also, levels of the anti-apoptotic proteins, Bcl-2 and Bcl-xL were elevated in VHL-positive cells, consistent with the protection from apoptotic stimuli. UV treatment led to increased S phase in VHL-negative, but not VHL-positive cells. Thus, following UV irradiation, diminution of p21 and p27 levels resulted in a hyperproliferative state in VHL-negative cells, leading to apoptosis. These results suggest that loss of VHL function promotes apoptosis and may provide selective pressure toward cells that are able to escape apoptosis, leading to tumorigenesis.
 ...
PMID:The von Hippel-Lindau tumor suppressor gene protects cells from UV-mediated apoptosis. 1112 15

A small proportion of brain tumors are attributed to a genetic predisposition; however, the hereditary proportion is undetermined. This study evaluates the degree of familial aggregation of cancer in a large series of brain tumor patients. Our study included 5,088 relatives of 639 probands (3,810 first- and 1,278 second-degree), diagnosed with a glioma between June 1992 and June 1995 at The University of Texas M. D. Anderson Cancer Center, Houston, Texas, with diagnosis under age 65 years, and residents of the United States or Canada. We conducted an in-person or telephone interview with patients and/or their next-of-kin, and obtained family histories for the probands' first-degree (parents, siblings, offspring) and selected second-degree relatives (aunts, uncles, grandparents) using a sequential sampling strategy. Reported cancers were documented by medical records and/or death certificates (if the relative was deceased and medical records were unavailable). We conducted segregation analysis using the Pedigree Analysis Program (PAP). The analyses were divided into two categories: (1) all 639 families, and (2) a subset of families whose gliomas stained positive on p53 immunohistochemistry analysis. We demonstrated that a multifactorial Mendelian model was favored, while a model postulating a purely environmental cause of brain cancer was rejected. This study indicates that familial cancer in relatives of glioma patients are probably a result of multigenic action, and familial clustering of cancer among relatives of glioma patients may involve unknown environmental exposures.
 ...
PMID:Segregation analysis of cancer in families of glioma patients. 1118 Apr 51

The CHK2 gene encodes a protein kinase that is important for the regulation of cell cycle arrest after DNA damage. CHK2 acts downstream of ataxia teleangiecstasia mutated (ATM), modulates the function of p53 and may help mediate cell cycle arrest at G2/M by phosphorylation of Cdc25C. Recently, the human homolog of the checkpoint kinase Cds1 (CHK2) has been suggested to be a tumor suppressor gene. Heterozygous germline mutations have been reported in Li-Fraumeni syndrome (LFS), a highly penetrant familial cancer phenotype, and in sporadic colon cancer. LFS is associated with the development of lymphoid malignancies, especially childhood ALL. Therefore, we analyzed the DNA from 143 lymphoid malignancies to determine whether they had mutations of the CHK2 gene. The 14 exons of CHK2 were studied by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) and sequencing of aberrantly migrating bands. One missense mutation changing serine to phenylalanine (codon 428) in an evolutionarily highly conserved domain was found in a non-Hodgkin's aggressive lymphoma. Another point mutation in the non-coding region was identified in one of adult T-cell leukemias (ATL) samples. This result suggests that mutation of the CHK2 gene may rarely be involved in the development of selected lymphomas.
 ...
PMID:Analysis of the CHK2 gene in lymphoid malignancies. 1169 18

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.
 ...
PMID:p53-mediated apoptosis and genomic instability diseases. 1176 63

AIM:To investigate the risk factors of esophageal cancer (EC) in urban areas of Xi'an and to determine the association between overexpression of P53 and these risk factors.METHODS: All cases (89) and controls (97) were permanent residents in urban areas of Xi'an, all cases of primary EC had been histologically confirmed, controls were inpatients with non-cancer and nonsmoking-related disease. Cancer tissues and tissues adjacent to the cancer of 65 cases and 24 available normal esophageal tissues of controls were detected for P53 overexpression by the immunohistochemical method.RESULTS: The smoking and familial history of cancer were significantly associated with EC in Xi'an inhabitants. The laboratory assay indicated that P53 positive stain in EC was 50.0%(34/65)and 6.1%(4/65) in tissues adjacent to the cancer, but no positive stain was found in normal esophageal tissues of controls. The results showed that P53 overexpression in EC was closely related to smoking and cases with familial history of cancer.CONCLUSION: Smoking and familial cancer history were important risk factors for EC,and the alteration of P53 gene may be due to smoking and inheritance factors.
 ...
PMID:Overexpression of P53 and its risk factors in esophageal cancer in urban areas of Xi'an. 1181 33

In various studies of sporadic breast cancers, 40-70% were strongly positive for fragile histidine triad (Fhit) protein expression, whereas only 18% of BRCA2 mutant breast cancers demonstrated strong Fhit expression, suggesting that the BRCA2 repair function may be necessary to retain intact fragile common chromosome fragile site 3B(FRA3B)/FHITloci. In the current study, 22 breast tumors with deleterious BRCA1 mutations were analyzed for Fhit expression by immunohistochemistry in a case-control matched pair analysis. Loss of Fhit expression was significantly more frequent in the BRCA1 cancers compared with sporadic breast tumors (9% Fhit positive versus 68% Fhit positive), suggesting that the BRCA1 pathway is also important in protecting the FRA3B/FHIT locus from damage. To investigate the relationship between repair gene deficiencies and induction of chromosome fragile sites in vitro, we have analyzed the frequency of aphidicolin induction of chromosome gaps and breaks in PMS2-, BRCA1-, MSH2-, MLH1-, FHIT-, and TP53-deficient cell lines. Each of the repair-deficient cell lines showed elevated expression of chromosome gaps and breaks, consistent with the proposal that proteins involved in mismatch and double-strand break repair are important in maintaining the integrity of common fragile regions. Correspondingly, genes at common fragile sites may sustain elevated levels of DNA damage in cells with deficient DNA repair proteins such as those mutated in several familial cancer syndromes.
 ...
PMID:The fragile histidine triad/common chromosome fragile site 3B locus and repair-deficient cancers. 1212 41

Anticipation in the age at onset of cancer in successive generations was described in several familial cancer syndromes. Based on multiple statistical analyses of a database of families with germline TP53 mutations, and using several different approaches and measures to eliminate possible biases, we show that anticipation may be a feature of the Li-Fraumeni syndrome. Definitive proof of anticipation in pedigrees with germline TP53 mutations will require more family data and further analysis, as well as research on the role of the p53 protein in processes like genome stability, which may represent the biological basis of anticipation in these families. This should have important practical implications for genetic testing, counselling, and preventative care for individuals at risk.
 ...
PMID:Is there anticipation in the age at onset of cancer in families with Li-Fraumeni syndrome? 1218 37

Multiple endocrine neoplasia type 1 (MEN1) is a familial cancer syndrome characterized mostly by tumors of the parathyroids, pancreas and anterior pituitary. The gene responsible, MEN1, encodes Menin, a 610 aminoacid nuclear protein with no sequence homology to other proteins. Although a mouse knock-out model is available, the function of Menin is still elusive. Proteins of known function are shown to interact with Menin: JunD, nuclear factor-KappaB, Smad3, Pem, Nm23H1, glial fibrillary acidic protein, Vimentin, and probably P53. Their partnership with Menin may correspond to a regulation of their activity, but their relevance to the various traits of MEN1 pathogenicity is not established. This raises fundamental issues on the regulation pathways implicated in this complex endocrine disease.
 ...
PMID:Menin interacting proteins as clues toward the understanding of multiple endocrine neoplasia type 1. 1244 71

Loss of tumour suppressor function is a common mechanistic step in deregulated cell growth and neoplasia. The p53 tumour suppressor gene is the most frequently mutated gene in cancer, and is inactivated in approximately 50% of human tumours. Mutation of p53 is also the predominant molecular basis of the Li-Fraumeni familial cancer susceptibility syndrome. p53 is a transcription factor that functions to regulate the integrity of the genome in response to DNA damage by inducing genes that promote cell cycle arrest, cell death, or repair of damaged DNA. These various effects exerted by p53 ensure that mutations do not pass on to subsequent generations, thus avoiding the presence of cells with multiple genetic hits that predispose the cell to neoplastic growth. Analysis of p53 functions using genetically-modified mice has complimented studies performed with human cancer tissue or cultured cells, and has greatly expanded knowledge about the role of p53 in tumour suppression. This finer understanding of p53 function has greatly facilitated research into small-molecule and other drug modifications of p53 activity as treatment modalities for the many human cancers bearing altered p53 function. This review will examine mouse models containing p53 modifications, and access the contribution of these studies to the understanding of p53-mediated tumour suppression.
 ...
PMID:Analysing p53 tumour suppressor functions in mice. 1255 5


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>