title: CYP17 gene polymorphism in relation to breast cancer risk: a case-control study.
abstract: BACKGROUND
  The c.1-34T>C 5' promoter region polymorphism in cytochrome P450c17 (CYP17), a key enzyme in the biosynthesis of estrogen, has been associated with breast cancer risk, but most previous studies have been relatively small.
  
  
  METHODS
  We genotyped 1,544 incident cases of primary breast cancer and 1,502 population controls, all postmenopausal Swedish women, for the CYP17 c.1-34T>C polymorphism and calculated odds ratios (ORs) and 95% confidence intervals (CIs) from logistic regression models.
  
  
  RESULTS
  No overall association was found between CYP17 c.1-34T>C and breast cancer risk, OR 1.0 (95% CI 0.8-1.3) for the A2/A2 (CC) carriers compared to the A1/A1 (TT) carriers, regardless of histopathology. We detected an interaction between CYP17 c.1-34T>C and age at menarche (P = 0.026) but regarded that as a chance finding as no dose-response pattern was evident. Other breast cancer risk factors, including menopausal hormone use and diabetes mellitus, did not modify the overall results.
  
  
  CONCLUSIONS
  It is unlikely that CYP17 c.1-34T>C has a role in breast cancer etiology, overall or in combination with established non-genetic breast cancer risk factors.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden. Kristjana.Einarsdottir@meb.ki.se
authors.forename: Kristjana
authors.initials: K
authors.lastname: Einarsdóttir
authors.forename: Tove
authors.initials: T
authors.lastname: Rylander-Rudqvist
authors.forename: Keith
authors.initials: K
authors.lastname: Humphreys
authors.forename: Susanne
authors.initials: S
authors.lastname: Ahlberg
authors.forename: Gudrun
authors.initials: G
authors.lastname: Jonasdottir
authors.forename: Elisabete
authors.initials: E
authors.lastname: Weiderpass
authors.forename: Kee Seng
authors.initials: KS
authors.lastname: Chia
authors.forename: Magnus
authors.initials: M
authors.lastname: Ingelman-Sundberg
authors.forename: Ingemar
authors.initials: I
authors.lastname: Persson
authors.forename: Jianjun
authors.initials: J
authors.lastname: Liu
authors.forename: Per
authors.initials: P
authors.lastname: Hall
authors.forename: Sara
authors.initials: S
authors.lastname: Wedrén
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D017698:Postmenopause; D013254:Steroid 17-alpha-Hydroxylase / Q000235:genetics*
chemical_list: D013254:Steroid 17-alpha-Hydroxylase