This study aims to evaluate the effect of various factors, such as exercise, diet, vitamin, supplement, and medication use, on selenium levels in BRCA1 and BRCA2 carriers. In addition, this study will also evaluate serum and toenail concentrations of selenium in relation to ovarian and breast cancer risk in this subpopulation.

Background:
A recent study demonstrated that serum selenium level was a strong predictor of cancer among BRCA1 mutation carriers. This data rejects the current thinking of selenium as a potential chemopreventive supplement and raises concern that it may actually have a detrimental effect on cancer risk in this subpopulation. Currently, there is no consensus regarding the dietary intake of selenium and cancer risk, or the blood levels of selenium and cancer risk.

Who Can Participate?
Participation in this study is completely voluntary. Only women who fulfill all of the following criteria may participate:

• Women who carry a BRCA1 or BRCA2 gene mutation
• Women who are 35-65 years of age

Why Participate?
By participating in this study, you will help us to understand which lifestyle factors influence selenium levels in BRCA1 and BRCA2 mutation carriers, and if selenium levels affect the risk for breast cancer and ovarian cancer in this subpopulation. This data may establish the potential for using selenium as a biomarker for the prevention of cancer in this population of BRCA carriers. Thus, this study will contribute to the future clinical guidelines for preventive counseling of this high-risk population.

What Does Participation Entail?
Participation entails completing one questionnaire, which asks about lifestyle factors including dietary intake, and physical activity. This study also requires you to provide a toenail, blood and urine sample so that selenium levels can be evaluated and related to breast and ovarian cancer risk. You may stop participation at any time. We estimate that the questionnaire will take less than 10 minutes to complete. An appointment at the Familial Breast Cancer Research Unit is also required for the collection of a blood and urine sample. The visit is estimated to take about 15 minutes.

Participation
If you wish to participate, please ensure that you are enrolled in the Risk Factor Analysis for Hereditary Breast and Ovarian Cancer study. You may also call the study coordinator at 416-351-3800 x 2732 or send an email at Kristi.DeBuono@wchospital.ca to request a package or to receive more information before making your decision.