title: Toenail selenium status and DNA repair capacity among female BRCA1 mutation carriers.
abstract: Selenium is an important cofactor of various antioxidant enzymes and has been shown to enhance DNA repair in normal human fibroblasts. Oral selenium supplementation has also been shown to decrease the number of chromosome breaks in BRCA1 mutation carriers. Because the predisposition to cancer among BRCA1 mutation carriers may be linked to high rates of DNA damage and chromosome breakage, we evaluated the association between toenail selenium concentrations and three measures of DNA repair capacity (the single-cell alkaline gel electrophoresis (comet) assay, the micronucleus test, and the enumeration of gamma-H2AX nuclear foci) in female BRCA1 mutation carriers and in non-carriers. Toenail selenium levels were inversely associated with levels of chromosomal damage following exposure to gamma-irradiation, as assessed by the micronucleus test. This association was limited to women with a BRCA1 mutation (p = 0.03). Toenail selenium was not a significant predictor of DNA repair capacity, as quantified by either the comet assay or the number of gamma-H2AX foci, in carriers or in non-carriers. These results provide evidence for a possible protective effect of selenium against BRCA1-associated breast cancers.
authors.affiliation: Women's College Research Institute, 790 Bay Street, Toronto, Ontario, Canada. joanne.kotsopoulos@wchospital.ca
authors.forename: Joanne
authors.initials: J
authors.lastname: Kotsopoulos
authors.forename: Zhou
authors.initials: Z
authors.lastname: Chen
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Vallis
authors.forename: Aletta
authors.initials: A
authors.lastname: Poll
authors.forename: Parviz
authors.initials: P
authors.lastname: Ghadirian
authors.forename: Greg
authors.initials: G
authors.lastname: Kennedy
authors.forename: Peter
authors.initials: P
authors.lastname: Ainsworth
authors.forename: Steven A
authors.initials: SA
authors.lastname: Narod
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D020552:Comet Assay; D004260:DNA Repair / Q000235:genetics*; D005260:Female; D019398:Genes, BRCA1; D006579:Heterozygote; D006657:Histones / Q000032:analysis; D006801:Humans; D015162:Micronucleus Tests; D008875:Middle Aged; D009154:Mutation; D009262:Nails / Q000737:chemistry*; D012643:Selenium / Q000032:analysis*
chemical_list: C468783:H2AX protein, human; D006657:Histones; D012643:Selenium