Annual physical examination

JF is a 26-year-old woman in the clinic today for her annual physical examination. As you take her medical history, it becomes apparent that she is quite concerned about her risk for developing breast cancer. Her mother and a maternal aunt both developed breast cancer in their late 40s. JF has heard that genetic testing can be done to see whether she carries “breast cancer genes.” Assuming JF is talking about the BRCA1 and BRCA2 genes, explain the role that these genes have in the genetic mechanisms of breast cancer.