How Do Genetic Determinants of Bone Mass Relate to Breast Cancer Risk?
Final rept. 1 Aug 1998-31 Dec 2001
WAYNE STATE UNIV DETROIT MI
Pagination or Media Count:
The purpose of this study is to investigate the relationship between breast cancer risk, bone mass, and two polymorphic hormone receptor genes-- the estrogen receptor ER and vitamin D receptor VDR genes. We also planned to explore a possible functional mechanism to explain this association. Our target was to recruit 200 new breast cancer cases and 200 controls, ages 40-85, with equal numbers of African-Americans and whites. Bone mineral density BMD measurements of the forearm were to be obtained. We have enrolled 231 cases and 198 controls, with an age range of 39-84 years. There is an equitable distribution of the two ethnic groups, with 50.3 of the cohort being white and 49.7 African-American. We enrolled more than 400 subjects because some individuals changed their minds about giving blood, some blood samples were not analyzable, and some subjects have no bone density data due to instrument malfunctions. Genotype frequencies of the VDR and ER gene segments that we investigated were not significantly different in cases or controls. However BMD expressed as a z-score in the proximal radius of the cases is significantly higher than controls, as hypothesized. Furthermore, the odds ratio associated with having higher than average bone density was 1.98 95 C.I. 1.32-2.97. This is our most significant and clinically relevant finding. Adjustment for potential confounders did not appreciably change this odds ratio. We are in the process of obtaining tumor tissue samples from subjects who are homozygous and who have given consent to our using their tissue for our final objective--to investigate the responsivity to estrogen of the polymorphic ER genotypes.
- Genetic Engineering and Molecular Biology
- Medicine and Medical Research