About 12% of women in the general population will develop breast cancer sometime during their lives.
By contrast, 55 – 65% of women who inherit a harmful BRCA1 mutation will develop breast cancer by age 70 years.
Similarly, for women who inherit a harmful BRCA2 mutation, the chances are 45%.
A negative result usually means the person is not at increased risk for developing cancer.
A positive result indicates increased risk for developing cancer.