Association between CYP17 gene polymorphism and risk of breast cancer in young women

Int J Cancer. 1999 Aug 20;84(4):350-3. doi: 10.1002/(sici)1097-0215(19990820)84:4<350::aid-ijc3>;2-l.


Long-term exposure to oestrogens is a well-recognised risk factor for breast cancer, whereas little is known about the influence of polymorphisms of genes involved in oestrogen biosynthesis and metabolism. A candidate, containing a single bp polymorphism, T-->C, (designated, A2 allele), might be the CYP17 gene, which codes for an enzyme involved in oestrogen synthesis. This polymorphism creates an additional Sp1-type promoter site (CCACC box), which has been shown to be associated with increased serum oestrogen levels. We performed a case-control study, to evaluate association of the CYP17 gene polymorphism with risk of breast cancer in young women (younger than 37 years). We found a statistically significant increased risk in carriers of at least 1 A2 allele [odds ratio (OR), 2.0; 95% confidence interval (CI), 1.1-3.5, p = 0.027], and a trend toward a gene-dose effect illustrated by a slightly higher risk for A2-homozygous subjects (OR, 2.8) than for heterozygous women (OR, 1. 9). Furthermore, when we investigated the CYP17 genotype in relation to tumour characteristics, breast cancer patients with 1 or 2 A2 alleles tended to have lower oestrogen receptor levels (risk ratio, 0.70; CI, 0.41-1.2, p = 0.44). Our findings suggest that CYP17 gene polymorphism influences breast carcinogenesis in young women. Int. J. Cancer (Pred. Oncol.) 84:350-353, 1999.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age Factors
  • Alleles
  • Base Sequence
  • Breast Neoplasms / epidemiology*
  • Breast Neoplasms / genetics*
  • Breast Neoplasms / mortality
  • Breast Neoplasms / pathology
  • Cell Cycle
  • Confidence Intervals
  • Female
  • Genetic Carrier Screening
  • Humans
  • Lymphatic Metastasis
  • Odds Ratio
  • Point Mutation
  • Polymorphism, Genetic*
  • Predictive Value of Tests
  • Promoter Regions, Genetic*
  • Receptors, Estrogen / analysis
  • Receptors, Progesterone / analysis
  • Risk Factors
  • Steroid 17-alpha-Hydroxylase / genetics*
  • Survival Analysis
  • Sweden / epidemiology


  • Receptors, Estrogen
  • Receptors, Progesterone
  • Steroid 17-alpha-Hydroxylase