title: Urinary biomarkers of oxidative stress and breast cancer survival.
abstract: OBJECTIVE
  Systemic oxidative stress has been implicated in the pathogenesis and progression of many chronic diseases, including breast cancer. No studies have investigated F2-isoprostanes (F2-IsoPs), valid biomarkers of systemic oxidative stress, in association with breast cancer prognosis. We conducted a nested case-control study in a prospective breast cancer survivor cohort to investigate systemic oxidative stress and survival.
  
  
  METHODS
  Urinary levels of F2-IsoPs and its major urinary metabolite (2,3-dinor-5,6-dihydro-15-F2t-IsoP, F2-IsoP-M) were measured post-cancer treatment using gas chromatography/negative ion chemical ionization mass spectrometry for 57 deceased breast cancer patients (cases) and 103 surviving patients (controls) matched 1:2 on age at diagnosis, stage, and diagnosis year. Odds ratios (ORs) and 95 % confidence intervals (CIs) were derived from conditional logistic regression models.
  
  
  RESULTS
  In unadjusted models, elevated F2-IsoP levels categorized based on the median value [≥1.73; <1.73 (reference)] were nonsignificantly inversely associated with mortality (OR 0.51, 95 % CI 0.24-1.10). After adjustment for potential confounders, elevated F2-IsoP levels were significantly associated with mortality (OR 0.36, 95 % CI 0.14-0.96). The inverse association was marginally significant when F2-IsoP was categorized based on tertiles (p trend = 0.08). In contrast, elevated F2-IsoP-M levels, categorized based on the median level [≥0.91; < 0.91(reference)], were associated with a statistically nonsignificant increased risk of mortality in both unadjusted and adjusted models (adjusted OR 1.39, 95 % CI 0.62-3.09).
  
  
  CONCLUSIONS
  Results suggest a role for oxidative stress biomarkers in breast cancer survival; however, as this is the first study to date, additional larger studies are needed.
authors.affiliation: Division of Epidemiology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA, sarah.nechuta@vanderbilt.edu.
authors.forename: Sarah
authors.initials: S
authors.lastname: Nechuta
authors.forename: Qiuyin
authors.initials: Q
authors.lastname: Cai
authors.forename: Ying
authors.initials: Y
authors.lastname: Zheng
authors.forename: Ginger L
authors.initials: GL
authors.lastname: Milne
authors.forename: Hui
authors.initials: H
authors.lastname: Cai
authors.forename: Qi
authors.initials: Q
authors.lastname: Dai
authors.forename: Gong
authors.initials: G
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.forename: Xiao Ou
authors.initials: XO
authors.lastname: Shu
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000652:urine*; D001943:Breast Neoplasms / Q000401:mortality* / Q000652:urine*; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D028441:F2-Isoprostanes / Q000652:urine*; D005260:Female; D006801:Humans; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology*; D011379:Prognosis; D016019:Survival Analysis; D017741:Survivors; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D028441:F2-Isoprostanes