W7 - Genome-wide Scan on Breast Cancer, CHD, and Stroke
This page provides study documentation for Core Study W7. For description of the specimen results, see Specimen Results Description (open to public). Data sets of the specimen results are included in the existing WHI datasets located on the WHI Data on this site (sign in and a completed Data Distribution Agreement are required; see details on the Data site).
Investigator Names and Contact Information
Core study approved by WHI Steering Committee
Introduction/Intent
The WHI hormone trials were designed to evaluate the hypothesis that postmenopausal hormone therapy would reduce coronary heart disease risk. The E alone trial was stopped on March 1, 2004 and preliminary data indicate no increase or decrease in risk of CHD over the trial duration; however, there was a modest and non-significant increase in risk in the first two years balanced by a possible risk reduction in the final years. In contrast to the findings for the E+P trial, in the E alone trial there was a trend towards lower risk of breast cancer. There was an increase in risk for stroke of about the same magnitude in both trials. The study group is committed to trying to understand the pathophysiologic basis for the variation in risk of these diseases with the use of E+P and E-alone, as well as contributing to the overall understanding of the genetics of these diseases.
If characteristics can be identified which distinguish the women at risk for adverse drug effects, they could avoid hormones while women who are not at risk could take them for menopausal symptoms and bone preservation. Clinical characteristics and conventional biomarkers have not proven sufficient for this purpose. This is a unique opportunity to blend the special resource of the WHI CTs with state-of-the-art basic science and in genetic epidemiology and pharmacogenomics.
Study goals are to 1) identify genes that lead to better understanding of E+P and E-alone effects on CHD and breast cancer, 2) identify genes predicting disease risk. We propose to a 2-step approach to enhance efficiency: First, 16 DNA pools will be formed (E+P vs. E-alone, CHD vs. breast cancer, active vs. placebo, case vs. matched controls). Then the most promising 3% of SNPs (~6000) from step 1 will be selected for individual genotyping . After DNA from each of the cases and controls is individually tested for each of the ~6000 SNPs, the most promising ~100 candidates will be identified for each clinical outcome. The WHI Observational Study will provide for validation studies of candidates identified.
Results/Findings