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)

We have developed a multiplex PCR/ligase detection reaction (PCR/LDR) that combines high sensitivity with the ability to simultaneously detect hundreds of mutations in a single-tube reaction. To enable us to rapidly assay large numbers of samples, we have linked this mutation detection scheme with analysis on a Universal DNA microarray. We have successfully applied this approach to characterize K-ras and p53 mutations in DNA derived from undissected colon tumors. The sensitivity of the assay has also facilitated detection of low-frequency mutations in BRCA1 and BRCA2 in pooled samples of DNA; thus, PCR/LDR can rapidly screen large numbers of DNA samples required for population studies.
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PMID:Mutation detection in K-ras, BRCA1, BRCA2, and p53 using PCR/LDR and a universal DNA microarray. 1081 94

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

Recent studies have elucidated some of the molecular and cellular mechanisms that determine the sensitivity or resistance to ionizing radiation. These findings ultimately may be useful in devising new strategies to improve the therapeutic ratio in cancer treatment. Despite the rapid advances in knowledge of cellular functions that affect radiosensitivity, we still cannot account for most of the clinically observed heterogeneity of normal tissue and tumor responses to radiotherapy, nor can we accurately predict which individual tumors will be controlled locally and which patients will develop more severe normal tissue damage after radiotherapy. However, several candidate genes for which deletion or loss of function mutations may be associated with altered cellular radiosensitivity (e.g., ATM, p53, BRCA1, BRCA2, DNA-PK) have been identified. Some of the differences in normal tissue sensitivity to radiation may stem from mutations with milder effects, heterozygosity, or polymorphisms of these genes. Finally, molecular mechanisms linking genetic instability, radiosensitivity, and predisposition to cancer are being unraveled.
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PMID:Biological basis of radiation sensitivity. Part 2: Cellular and molecular determinants of radiosensitivity. 1085 63

A single germ line mutation in BRCA1, (185delAG) is detected in a substantial portion of Jewish Israeli patients with ovarian cancer. Whether disease phenotypes differ in BRCA1 mutation carriers and sporadic cases is presently a subject for debate. To gain insight into this issue, we analysed tumours from 65 Jewish women with ovarian cancer, 29 (45%) were 185delAG BRCA1 mutation carriers, and 36 (55%) were non-carriers of any of the predominant Jewish mutations in BRCA1 or BRCA2 (sporadic). In 19/29 mutation carriers (66%) diagnosis was made prior to age 60 years, compared with 14/36 (39%) of the non-carriers (P=0.03; Yates corrected P=0.06). Low malignant potential ('borderline') tumours were detected less frequently among carriers (2/29; 7%) than non-carriers (9/36; 25%) (P=0.03; one tail P=0.05). Immunohistochemical analysis in invasive carcinoma (n=54) showed that 17/27 carriers (63%) and 18/27 non-carriers (67%) had positive nuclear staining with a p53 antibody. In 4/27 carriers (15%) and 3/25 non-carriers (12%), 25% or more of the tumour cells stained positive for Ki-67, an insignificant difference. Results were not altered by including borderline tumours (n=11) in these analyses. We conclude that the rate of TP53 inactivation and proliferative index in ovarian cancer, are similar for 185delAG BRCA1 mutation carriers and sporadic cases.
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PMID:Immunohistochemical analyses of sporadic and familial (185delAG carriers) ovarian cancer in Israel. 1085 45

Germline mutations of BRCA1 predispose women to breast and ovarian cancers. BRCA1 contains several functional domains that interact directly or indirectly with a variety of molecules, including tumor suppressors (p53, RB, BRCA2 and ATM), oncogenes (c-Myc, casein kinase II and E2F), DNA damage repair proteins (RAD50 and RAD51), cell-cycle regulators (cyclins and cyclin-dependent kinases), transcriptional activators and repressors (RNA polymerase II, RHA, histone deacetylase complex and CtIP) and others. Mounting evidence indicates that these physical associations are not artifacts; rather, BRCA1 is likely to serve as an important central component in multiple biological pathways that regulate cell-cycle progression, centrosome duplication, DNA damage repair, cell growth and apoptosis, and transcriptional activation and repression. This review examines our understanding of the significance of the interactions between BRCA1 and other proteins, through which BRCA1 maintains genome integrity and represses tumor formation. Published 2000 John Wiley & Sons, Inc.
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PMID:Roles of BRCA1 and its interacting proteins. 1091 3

Breast cancer is considered to display a high degree of intratumor heterogeneity, without any obvious morphological and pathological steps to define sequential evolution, and its progression may vary among individual tumors. In an attempt to elucidate these etiological and phenotypic complexities, the present study, based on the fundamental concept that genomic instability is the engine of both tumor progression and tumor heterogeneity, was conducted to test the hypothesis that breast cancer pathogenesis is driven by double-strand break (DSB)-initiated chromosome instability (CIN). The rationale underlying this hypothesis is derived from the clues provided by family breast cancer syndromes, in which susceptibility genes, including p53, ATM, BRCA1 and BRCA2, are involved within the common functional pathway of DSB-related checkpoint/ repair. Because genomic deletion caused by DSB is reflected in the genetic mechanism of loss of heterozygosity (LOH), this genome-wide LOH study was conducted, using 100 tumors and 400 microsatellite markers. To minimize the effect of heterogeneity within tumors, the experimental technique of laser capture microdissection was used to ensure that genetic and phenotypic examinations were based on the same tumor cells. Support for our hypothesis comes from the observations that: (a) the extent of DSB-initiated CIN in tumors significantly increased as tumors progressed to poorer grades or later stages; (b) in the sequential steps toward CIN, the loci of p53 and ATM, the key checkpoint genes against DSB, were lost at the earliest stage; and (c) many loci identified to be important in breast tumorigenesis were the genomic sites possibly harboring the genes involved in DSB-related checkpoint/repair (including RAD51, RAD52, and BRCA1) or CIN (including FA-A, FA-D, and WRN), and a higher number of these loci showing LOH was significantly associated with increased level of DSB-initiated CIN (P < 0.0001). Breast cancers are thus considered to be sequentially progressive with CIN. However, CIN might also cause genetic heterogeneity, which was revealed by the findings that LOH at some markers was observed only in the component of ductal carcinoma in situ but not in the invasive component of the same tumors. In addition, some markers were found to preferentially lose at specific tumor grades, implying their contribution to genetic heterogeneity during tumor development. Therefore, this study suggests that breast cancer progression is clonal with regard to CIN, but different breast cancers would present distinct molecular profiles resulting from genetic heterogeneity caused by CIN.
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PMID:Genome-wide search for loss of heterozygosity using laser capture microdissected tissue of breast carcinoma: an implication for mutator phenotype and breast cancer pathogenesis. 1091 64

The hereditary breast (BC) and ovarian (OC) cancer syndrome (HBOC) includes genetic alterations of various susceptibility genes such as TP53, ATM, PTEN or MSH2, MLH1, PMS1, PMS2, MSH3 and MSH6, BRCA1 and BRCA2. Germline mutations of the cancer-susceptibility genes BRCA1 and BRCA2 seem to be the major aetiology of the HBOC. Genetic counselling and identification of high-risk families may be essential (1) to provide the best method for genetic testing by explaining the sensitivity and specificity of the methods, (2) to offer the opportunity to participate in specific early cancer detection programmes (breast (self) palpation, ultrasound, mammography and magnetic resonance tomography for breast cancer; vaginal exploration and ultrasound for ovarian cancer), (3) to inform them about prophylactic medication (oral contraceptive pill (OCP), chemoprevention (tamoxifen, raloxifen, aromatase inhibitors)) or surgery (bilateral prophylactic mastectomy or oophorectomy) and (4) to provide individualized psychological support. To fulfil these broad demands, an inter-disciplinary counselling approach (gynaecological oncology, human genetics, molecular biology, psychotherapy) in the setting of a cancer genetic clinic seems the most appropriate. There, participation in predictive genetic testing or the use of preventive or therapeutic options may be discussed extensively with the subjects. In particular, preventive options are emotionally disturbing for the subjects, and in cases of previous cancer. BC chemoprevention for high-risk women does not seem to be as effective as expected. However, OCP reduces the risk for OC. For prophylactic surgery, various points have to be considered, including: (1) individual risk assessment and gain in life expectancy, (2) value of screening and early detection methods or medical prevention, (3) disease characteristics and prognosis, and (4) anxiety and quality of life. Decisions regarding these options have to be individualized and psychological support must be offered during the period of decision and follow-up.
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PMID:Prevention and therapy for BRCA1/2 mutation carriers and women at high risk for breast and ovarian cancer. 1095 53

We have provided an overview of recent studies that have greatly expanded our knowledge of the molecular and cellular mechanisms that determine the sensitivity or resistance to ionizing radiation. Much of this knowledge was obtained by studying tumor and nontumor cell types that under- or overexpress proteins involved in the regulation of the DNA damage response, cell cycle progression, growth factor signal transduction, and apoptosis. These findings may ultimately be useful in devising new strategies to improve the therapeutic ratio in cancer treatment. Despite the rapid advances in knowledge of cellular functions that affect radiosensitivity, we still cannot account for most of the clinically observed heterogeneity of normal tissue and tumor responses to radiotherapy; nor can we accurately predict which individual tumors will be locally controlled and which patients will develop more severe normal tissue damage after radiotherapy. However, several candidate genes for which deletion or loss of function mutations may be associated with altered cellular radiosensitivity (e.g., ATM, p53, BRCA2) have been identified. Some of the differences in normal tissue sensitivity to radiation may occur because of mutations with milder effects, heterozygosity, or polymorphisms of these genes. Finally, molecular mechanisms linking genetic instability, radiosensitivity, and predisposition to cancer are being examined.
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PMID:The molecular and cellular basis of radiosensitivity: implications for understanding how normal tissues and tumors respond to therapeutic radiation. 1099 50

Germline mutations in the breast cancer-associated genes BRCA1 and BRCA2 confer a lifetime risk of malignancy. Distinctive morphological features have been attributed to these familial tumours; however, in sporadic breast cancer, the inter-relationship between loss of heterozygosity (LOH) of these loci and tumour morphology remains to be fully elucidated. We studied a series of 120 sporadic breast carcinomas using microsatellite markers to identify LOH of BRCA1, BRCA2, p53 and PTEN. The associations between loss at each of the loci were examined and related to tumour morphology. LOH of the 4 loci did not occur independently; there were highly significant associations between LOH of BRCA1 and both BRCA2 (p < 0.001) and p53 (p < 0.001). LOH at all 4 loci was significantly associated with a high degree of nuclear pleomorphism. Tumours with LOH of BRCA1 also had high mitotic indices, few tubules and a paucity of DCIS, all of which are morphological features similar to those described for familial cases. Following Bonferroni's correction for multiple tests, we found that the tumours with LOH of BRCA1 were still significantly associated with a high mitotic index (p = 0.0006) and a high degree of nuclear pleomorphism (p = 0.001).
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PMID:Association between loss of heterozygosity of BRCA1 and BRCA2 and morphological attributes of sporadic breast cancer. 1100 69

About one in eight to ten women living in Western countries will develop breast cancer during her lifetime and between 5-10% of these cases result from an inherited susceptibility to the disease. Within the past few years, a number of genes associated with a high risk of breast cancer have been identified, including BRCA1, BRCA2, TP53, PTEN, MLH1, MSH2, and STK11. The identification of these genes, together with the rapid advances in molecular genetic analyses, should improve the diagnosis and therapy of breast cancer. This article reviews the genetic basis of hereditary breast cancer, in particular the contribution of BRCA1 and BRCA2 and discusses the clinical application of this new molecular knowledge with regard to molecular testing, surveillance and prevention in women with a hereditary predisposition to breast cancer.
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PMID:Hereditary breast cancer: high risk genes, genetic testing and clinical implications. 1103 30


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