title: Single-nucleotide polymorphisms within the antioxidant defence system and associations with aggressive prostate cancer.
abstract: OBJECTIVE
  To study the effects of oxidative stress on prostate cancer development as the exact biological mechanisms behind the relationship remain uncertain. We previously reported a statistically significant interaction between circulating selenium levels, variants in the superoxide dismutase 2 gene (SOD2; rs4880), and risk of developing prostate cancer and presenting with aggressive prostate cancer.
  
  
  METHODS
  We genotyped men with localized/regional prostate cancer for 26 loci across eight genes that are central to cellular antioxidant defence: glutathione peroxidase (GPX1, GPX4), peroxisome proliferator-activated receptor γ coactivator (PPARGC1A, PPARGC1B), SOD1, SOD2, and SOD3, and 'X-ray repair complementing defective repair in Chinese hamster cell 1' (XRCC1). Among 489 men, we examined the relationships between genotypes, circulating selenium levels, and risk of presenting with aggressive prostate cancer at diagnosis, as defined by stage, grade and prostate-specific antigen (PSA) level (213 aggressive cases).
  
  
  RESULTS
  Two variants in SOD2 were significantly associated with the risk of aggressive prostate cancer (rs17884057, odds ratio 0.83, 95% confidence interval 0.70-0.99; and rs4816407, 1.27, 1.02-1.57); men with A alleles at rs2842958 in SOD2 had lower plasma selenium levels (median 116 vs 121.8 µg/L, P= 0.03); and the association between plasma selenium levels and risk of aggressive prostate cancer was modified by SOD1 (rs10432782) and SOD2 (rs2758330).
  
  
  CONCLUSIONS
  While this study was cross-sectional and these associations might be due to chance, further research is warranted on the potential important role of antioxidant defence in prostate cancer.
authors.affiliation: Lank Center for Genitourinary Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
authors.forename: Miyako
authors.initials: M
authors.lastname: Abe
authors.forename: Wanling
authors.initials: W
authors.lastname: Xie
authors.forename: Meredith M
authors.initials: MM
authors.lastname: Regan
authors.forename: Irena B
authors.initials: IB
authors.lastname: King
authors.forename: Meir J
authors.initials: MJ
authors.lastname: Stampfer
authors.forename: Philip W
authors.initials: PW
authors.lastname: Kantoff
authors.forename: William K
authors.initials: WK
authors.lastname: Oh
authors.forename: June M
authors.initials: JM
authors.lastname: Chan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D000975:Antioxidants / Q000502:physiology*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D003430:Cross-Sectional Studies; D005838:Genotype; D005979:Glutathione Peroxidase / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D017430:Prostate-Specific Antigen / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology; D012643:Selenium / Q000097:blood; D013482:Superoxide Dismutase / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D000099156:Superoxide Dismutase 2
chemical_list: D000975:Antioxidants; D014408:Biomarkers, Tumor; D005979:Glutathione Peroxidase; D017430:Prostate-Specific Antigen; D012643:Selenium; D013482:Superoxide Dismutase; D014157:Transcription Factors; D000099156:Superoxide Dismutase 2; C111264:peroxisome-proliferator-activated receptor-gamma coactivator-1