Breast cancer takes its greatest toll on younger women, as it is the leading category of cancer deaths for women 20-39 years of age. Sadly, survival rates are lowest among women diagnosed at a young age. This impact is most significant among African-American women who have the highest incidence and mortality rate among women less than 45 years of age. The goal of our program is to identify the genetic factors which distinguish breast cancer in younger women compared to older women.