title: Menopausal status modifies breast cancer risk associated with the myeloperoxidase (MPO) G463A polymorphism in Caucasian women: a meta-analysis.
abstract: BACKGROUND
  Breast cancer susceptibility may be modulated partly through polymorphisms in oxidative enzymes, one of which is myeloperoxidase (MPO). Association of the low transcription activity variant allele A in the G463A polymorphism has been investigated for its association with breast cancer risk, considering the modifying effects of menopausal status and antioxidant intake levels of cases and controls.
  
  
  RESULTS
  To obtain a more precise estimate of association using the odds ratio (OR), we performed a meta-analysis of 2,975 cases and 3,427 controls from three published articles of Caucasian populations living in the United States. Heterogeneity among studies was tested and sensitivity analysis was applied. The lower transcriptional activity AA genotype of MPO in the pre-menopausal population showed significantly reduced risk (OR 0.56-0.57, p = 0.03) in contrast to their post-menopausal counterparts which showed non-significant increased risk (OR 1.14; p = 0.34-0.36). High intake of antioxidants (OR 0.67-0.86, p = 0.04-0.05) and carotenoids (OR 0.68-0.86, p = 0.03-0.05) conferred significant protection in the women. Stratified by menopausal status, this effect was observed in pre-menopausal women especially those whose antioxidant intake was high (OR 0.42-0.69, p = 0.04). In post-menopausal women, effect of low intake elicited susceptibility (OR 1.19-1.67, p = 0.07-0.17) to breast cancer.
  
  
  CONCLUSIONS
  Based on a homogeneous Caucasian population, the MPO G463A polymorphism places post-menopausal women at risk for breast cancer, where this effect is modified by diet.
authors.affiliation: School of Natural Sciences, Saint Louis University, Baguio City, Philippines.
authors.forename: Noel
authors.initials: N
authors.lastname: Pabalan
authors.forename: Hamdi
authors.initials: H
authors.lastname: Jarjanazi
authors.forename: Lillian
authors.initials: L
authors.lastname: Sung
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Hilmi
authors.initials: H
authors.lastname: Ozcelik
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000494:pharmacology; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000235:genetics*; D002338:Carotenoids / Q000494:pharmacology; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics*; D006801:Humans; D008593:Menopause / Q000235:genetics / Q000502:physiology*; D008875:Middle Aged; D016017:Odds Ratio; D009195:Peroxidase / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D044465:White People
chemical_list: D000975:Antioxidants; D002338:Carotenoids; D009195:Peroxidase