If you are tested positive, you'd be at very high risk for breast cancer
, for example BRCA2 positive women can be as high as 84% for breast
and 40% for ovca. Of course, noone really knows the % for sure. Two genes have been identified, BRCA1 and BRCA2.
If you are positive, at a minimum you should enroll in a high risk screening program that includes doc breast exams and alternating MRIs and digital mammograms every 6 months. Just being monitored by a doctor is not enough.