Breast Cancer Risk Factors

Families that have a history of multiple cases of both breast and ovarian cancer carry the highest risk for a mutation in BRCA1 or BRCA2. However, not every woman who has a harmful BRCA1 or BRCA2 mutation will develop breast or ovarian cancer.

About 12% of women in the general population will develop breast cancer at some point, compared to about 60% of women who have inherited a harmful mutation in BRCA1 or BRCA2. A woman who has inherited a harmful BRCA1 or BRCA2 mutation is about five times more likely to develop breast cancer than a woman without a mutation.

Estimates have concluded that inherited BRCA1 and BRCA2 mutations account for five-to-ten percent of breast cancers and 10-to-15 percent of ovarian cancers among Caucasian women in the United States.

  • General Breast Cancer Risk Factors
  • Age
  • Family History
  • Medical History
  • Hormonal Influences
  • Birth Control Pills
  • Hormone Replacement Therapy
  • Obesity
  • Physical Activity
  • Alcohol
  • High-Risk Populations

Some populations show a higher frequency of BRCA1 and BRCA2 mutations. For example, mutation of these two genes is the most common mutations found in the Ashkenazi Jewish population. Other ethnic populations that show higher frequencies of specific BRCA1 and BRCA2 mutations include the Norwegian, Dutch and Icelandic areas.

Learn about testing for breast cancer