According to the National Cancer Institute (NCI), the lifetime risk for a woman to develop breast cancer is 12.8 percent or one in eight, while the lifetime risk to develop ovarian cancer is 1.5 percent, or one in 67. About 80 percent of hereditary (inherited) breast cancer is caused by mutations in BRCA1 or BRCA2.
Approximately 5 percent to 10 percent of breast and ovarian cancers are due to known predisposing genetic factors. This means that the majority of breast and ovarian cancers are, in fact, not inherited.
There are several genetic syndromes associated with an increased risk for breast and/or ovarian cancer that require clinical care by a physician or other healthcare professional. Listed in the directory below are some, for which we have provided a brief overview.