Markers for Breast Cancer

This study will analyze blood samples to identify substances that are associated with the development of breast cancer. It will determine if: * Women who are diagnosed with a benign breast condition that is related to a considerably increased risk of breast cancer are more likely to have certain gene variants than women diagnosed with conditions related to very little increased breast cancer risk * Women with benign breast conditions who subsequently develop breast cancer are more likely to have certain gene variants than women with similar benign conditions who do not develop breast cancer. This study will examine blood samples from premenopausal women who underwent breast biopsy (removal of a small piece of breast tissue for microscopic examination) at four hospitals in Grand Rapids, MI, from 1977 to 1987 and were found to have benign breast disease. The women, who agreed to participate in a study of markers for breast cancer, also provided a blood sample and were interviewed for information on their breast cancer risk factors, family history of breast cancer, use of medications, and history of medical conditions. This study will retrieve the biopsy reports for these women, determine which of them later developed breast cancer, and perform genotyping on their blood samples. The information from this study may help in future diagnosis and treatment of breast cancer.