title: Tagging single-nucleotide polymorphisms in antioxidant defense enzymes and susceptibility to breast cancer.
abstract: It is generally believed that the initiation of breast cancer is a consequence of cumulative genetic damage leading to genetic alterations and provoking uncontrolled cellular proliferation and/or aberrant programmed cell death, or apoptosis. Reactive oxygen species have been related to the etiology of cancer as they are known to be mitogenic and therefore capable of tumor promotion. The aim of this study was to assess the role of common variation in 10 polymorphic genes coding for antioxidant defense enzymes in modulating individual susceptibility to breast cancer using a case-control study (N cases = 4,474 and N controls = 4,580). Both cases and controls were from the East Anglian region of the United Kingdom. We have identified a set of 54 single nucleotide polymorphisms (SNPs) that efficiently tag all the known SNPs in the 10 genes and are also expected to tag any unknown SNPs in each gene. We found no evidence for association of common variants in SOD1, SOD2, GPX1, GPX4, GSR, TXNRD1, and TXN2. There was borderline evidence for association of variants in CAT g27168a {P [2 degrees of freedom (df)] = 0.05}, TXN t2715c [P (2 df) = 0.007], and TXNRD2 A66S and TXNRD2 g23524a (P(trend) = 0.074 and 0.046, respectively). For TXNRD2 A66S [AS versus AA: odds ratio (OR), 1.05; 95% confidence intervals (95% CI), 0.96-1.15; SS versus AA: OR, 1.12; 95% CI, 0.98-1.29], there are bioinformatics data to suggest that it is functional but confirmation in independent data sets is required before they can be regarded as definitive breast cancer susceptibility alleles. Even if confirmed, these four alleles would account for just 0.32% of the excess familial risk of breast cancer.
authors.affiliation: Strangeways Research Laboratory, Cancer Research UK Department of Oncology, University of Cambridge,Worts Causeway, Cambridge CB1 8RN, UK. arancha@srl.cam.ac.uk
authors.forename: Arancha
authors.initials: A
authors.lastname: Cebrian
authors.forename: Paul D
authors.initials: PD
authors.lastname: Pharoah
authors.forename: Shahana
authors.initials: S
authors.lastname: Ahmed
authors.forename: Paula L
authors.initials: PL
authors.lastname: Smith
authors.forename: Craig
authors.initials: C
authors.lastname: Luccarini
authors.forename: Robert
authors.initials: R
authors.lastname: Luben
authors.forename: Karen
authors.initials: K
authors.lastname: Redman
authors.forename: Hannah
authors.initials: H
authors.lastname: Munday
authors.forename: Douglas F
authors.initials: DF
authors.lastname: Easton
authors.forename: Alison M
authors.initials: AM
authors.lastname: Dunning
authors.forename: Bruce A J
authors.initials: BA
authors.lastname: Ponder
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000975:Antioxidants / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics*; D016022:Case-Control Studies; D004739:England; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D017382:Reactive Oxygen Species
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D010088:Oxidoreductases