Association between the T27C polymorphism in the cytochrome P450 c17α (CYP17) gene and risk factors for breast cancer

Chi Chen Hong, Henry J. Thompson, Cheng Jiang, Geoffrey L. Hammond, David Tritchler, Martin Yaffe, Norman F. Boyd

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


Mammographic density is associated with increased breast cancer risk and is influenced by sex hormones. A T27C polymorphism (alleles A1 and A2, respectively) in the 5′ promoter region of CYP17 may be associated with elevated sex hormone levels. In a cross-sectional study of 181 pre- and 173 postmenopausal women, we examined the relationship of this polymorphism with mammographic density and other risk factors for breast cancer. Subjects were recruited across five categories of density. Risk factor and dietary information, anthropometric measures, and blood samples were obtained. Sex hormone, lipid, growth factor levels, and CYP17 genotypes were determined. CYP17 genotype was not associated with mammographic density levels before or after adjusting for risk factors for breast cancer. In premenopausal women, the A2 allele was associated with higher levels of dehydroepiandrosterone sulfate, and in post-menopausal women, with higher levels of total estradiol and lower levels of follicle stimulating hormone. Among premenopausal women, interactions were observed between CYP17 genotype and endogenous insulin levels as well as dietary variables associated with mammographic density. Our findings suggest that the CYP17 A2 allele is associated with hormone levels, and interacts with insulin levels and diet to affect breast density levels and potentially breast cancer risk.

Original languageEnglish (US)
Pages (from-to)217-230
Number of pages14
JournalBreast Cancer Research and Treatment
Issue number3
StatePublished - Dec 2004

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research


Dive into the research topics of 'Association between the T27C polymorphism in the cytochrome P450 c17α (CYP17) gene and risk factors for breast cancer'. Together they form a unique fingerprint.

Cite this