Author: Maria Shuk Mun Lam Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Bioactivation of environmental procarcinogens and prolonged exposure to 17ß-estradiol and catechol estrogens have been implicated in the etiology of mammary carcinogenesis. Endogenous 17ß-estradiol is oxidized to catechol estrogens by cytochrome P450 CYP1A2 and CYP1B1 enzymes which are transcriptionally regulated by the AH receptor. These enzymes are also involved in the bioactivation of numerous environmental procarcinogens such as benzo['a']pyrene. Consequently, those genetic polymorphisms in 'CYP1A2, CYP1B1' and 'AHR' that result in changes of enzyme or receptor function may affect 17ß-estradiol clearance and metabolic activation of procarcinogens. I genotyped two populations for a total of 7 polymorphisms in the 'AHR, CYP1A2' and ' CYP1B1' genes to examine whether these gene polymorphisms modify estrogen metabolism (Project 1) and breast cancer susceptibility (Project 2). Data of our estrogen metabolism study (Project 1) suggest that the 'AHR ' 554 polymorphism is related to alterations in 17ß-estradiol metabolism. Results of our Quebec French Canadian breast cancer case-control study (Project 2) indicate that the 'AHR' 554, 'CYP1A2*1F, CYP1B1*3' and 'CYP1B1*4' polymorphisms may modify breast cancer susceptibility.
Author: Marcelo Larramendy Publisher: BoD – Books on Demand ISBN: 9535121456 Category : Technology & Engineering Languages : en Pages : 172
Book Description
This edited book, Toxicity and Hazard of Agrochemicals, is intended to provide an overview of toxicology that examines the hazardous effects of common agrochemicals employed every day in our agricultural practices. Furthermore, it is hoped that the information in the present book will be of value to those directly engaged in the handling and use of agrochemicals and that this book will continue to meet the expectations and needs of all interested in the different aspects of human and environmental risk toxicities.
Author: P. Toniolo Publisher: ISBN: Category : Medical Languages : en Pages : 340
Book Description
This publication originates from an international workshop which addresses a range of methodological issues underlying the use of biological markers of exposure, biological effects and individual susceptibility in cancer epidemiology. It includes a report of the workshop, with a general discussion and recommendation on epidemiology. a series of peer-reviewed authored contributors provide a more personal view on the most important aspects by key researchers.
Author: Paolo Vineis Publisher: ISBN: Category : Medical Languages : en Pages : 530
Book Description
The study of interactions between genes and environmental exposures ha s expanded considerably in recent years. Highly penetrant genes that a re involved in familial cancer have been identified, but are likely to account for a relatively small proportion of total cancers. Other pre disposing genes have low penetrance, resulting in a moderate increase in the risk of specific cancers, but are widespread in the general pop ulation. This is the case for so-called metabolic polymorphisms. Scien tific interest in metabolic polymorphisms is based on the possibility of identifying subgroups of the population which are at elevated risk of developing environmentally-induced cancer. However, such studies ra ise a series of problems that are methodological - related to the stud y design and analysis - and ethical - related to the practical use tha t can be made of genetic information. This volume deals thoroughly wit h such problems.
Author: Chi-Chen Hong Publisher: National Library of Canada = Bibliothèque nationale du Canada ISBN: 9780612918108 Category : Languages : en Pages : 494
Book Description
The objective of this thesis was to study the genetic basis of ovarian hormone metabolism and its potential influence on mammographic density levels and other risk factors for breast cancer. Using a cross-sectional design, polymorphisms in 2 genes, P450 c17alpha (CYP17, T27C, A1 and A2 allele, respectively) and catechol-O-methyltransferase (COMT, VAL158MET, COMT*1 and COMT*2 allele, respectively), as well as cytochrome P450 1A2 (CYP1A2) activity were examined in their relationships with mammographic density, sex hormones, the growth hormone-insulin growth factor-I (IGF-1) axis, and anthropometric variables. Each low activity COMT*2 allele was associated with lower levels of percent breast density amongst pre- but not postmenopausal subjects. In premenopausal women the low activity COMT*2 allele was also associated with lower serum levels of IGF-1, higher levels of FSH and progesterone, and with a larger waist-to-hip ratio, body mass index (BMI), and subscapular skinfold. Information was obtained on risk factors, diet, and anthropometric measures. Blood levels of sex hormones, lipids, and growth factors were measured; and, CYP17 and COMT genotypes were determined. In vivo CYP1A2 activity was assessed by measuring caffeine metabolites in urine. Serum and urinary malondialdehyde (MDA), and MDA-deoxyguanosine adducts in DNA were measured. Mammograms were determined using a computer-assisted method. CYP17 genotype was not associated with mammographic density levels. In premenopausal women, the A2 allele was associated with higher levels of dehydroepiandrosterone sulfate, and in postmenopausal women, with higher levels of total estradiol and lower levels of follicle stimulating hormone. Among premenopausal subjects, interactions were observed between CYP17 genotype and endogenous insulin levels as well as various dietary variables. These findings indicate that CYP17 and COMT genotypes, as well as CYP1A2 activity are associated with several risk factors for breast cancer. CYPIA2 activity in post-, but not premenopausal, women was positively associated with breast density levels. In premenopausal women, CYP1A2 activity was associated with serum and urinary MDA levels, age, BMI, smoking status, and levels of sex hormone binding globulin (SHBG), total cholesterol, insulin, triglyceride, and caffeine intake. In postmenopausal subjects, independent associations were observed with smoking status, age at menarche, blood triglycerides, SHBG, and IGF-1 levels.
Author: Andrea Dunaif Publisher: Springer Science & Business Media ISBN: 1597451088 Category : Medical Languages : en Pages : 361
Book Description
This volume includes the latest diagnostic criteria for PCOS and comprises the most up-to-date information about the genetic features and pathogenesis of PCOS. It critically reviews the methodological approaches and the evidence for various PCOS susceptibility genes. The book also discusses additional familial phenotypes of PCOS and their potential genetic basis. All four editors of this title are extremely prominent in the field of PCOS.
Author: Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
The current study investigates whether polymorphisms in the CYP 17 gene, which plays roles in estrogen biosynthesis, are associated with an altered risk of breast cancer in a population-based sample of women (400 cases and 400 controls) who participated in the Long Island Breast Cancer Study Project (LIBSCP). In addition, we are also exploring whether the effects of reproductive risk factors and exposure to exogenous estrogen are modified by CYP 17 polymorphisms. In the past year, laboratory assays on CYP 17 polymorphisms are being conducted in the Division of Environmental Health Sciences of Columbia University. The polymorphisms are being determined by PCR-RFLP methods with a digestion by appropriate restriction enzymes. To date, assays on 300 cases and 300 controls have been performed. Delays in subject and sample selection in the parent LIBSCP study delayed Task 1, thus delaying the start of laboratory analyses. Therefore, Task 2 will not be completed until the end of September 1999. Entry of laboratory data to computers and merging of laboratory data with questionnaire data (Task 3) are estimated to begin in October 1999. Data analysis, manuscript preparation and report writing (Tasks 4 & 5) will take place in the coming year.
Author: Maria Shuk Mun Lam
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Author: Menghua Tao
Author: Marcelo Larramendy
Author: P. Toniolo
Author: Paolo Vineis![Influence of Genetic Polymorphisms in P450 C17α (T27C), Catechol-O-methyltransferase (VAL158MET), and Activity Level of Cytochrome P450 1A2 on Mammographic Density Levels and Other Risk Factors for Breast Cancer [microform] PDF](https://books.google.com/books/content/images/frontcover/2kHQygAACAAJ?fife=w80-h100)
Author: Chi-Chen Hong
Author: Andrea Dunaif
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