BRCA2 is a gene that increases the risk of getting breast and ovarian cancer in women and breast and prostate cancer in men. Out of every 100 women who have a faulty version of this gene, between 50 and 80 will develop breast cancer at some point in their life (50 to 80% lifetime risk). Ovarian cancer lifetime risk is about 20%. Male carriers have an increased risk of breast cancer and prostate cancer.