How do people know if they should consider genetic testing for BRCA1 and BRCA2 mutations?

Currently, there are no standard criteria for recommending or referring someone for BRCA1 or BRCA2 mutation testing.

In a family with a history of breast and/or ovarian cancer, it may be most informative to first test a family member who has breast or ovarian cancer. If that person is found to have a harmful BRCA1 or BRCA2 mutation, then other family members can be tested to see if they also have the mutation.

Regardless, women who have a relative with a harmful BRCA1 or BRCA2 mutation and women who appear to be at increased risk of breast and/or ovarian cancer because of their family history should consider genetic counseling to learn more about their potential risks and about BRCA1 and BRCA2 genetic tests.

The likelihood of a harmful mutation in BRCA1 or BRCA2 is increased with certain familial patterns of cancer. These patterns include the following:

• For women who are not of Ashkenazi Jewish descent:
  • two first-degree relatives (mother, daughter, or sister) diagnosed with breast cancer, one of whom was diagnosed at age 50 or younger;
  • three or more first-degree or second-degree (grandmother or aunt) relatives diagnosed with breast cancer regardless of their age at diagnosis;
  • a combination of first- and second-degree relatives diagnosed with breast cancer and ovarian cancer (one cancer type per person);
  • a first-degree relative with cancer diagnosed in both breasts (bilateral breast cancer);
  • a combination of two or more first- or second-degree relatives diagnosed with ovarian cancer regardless of age at diagnosis;
  • a first- or second-degree relative diagnosed with both breast and ovarian cancer regardless of age at diagnosis; and
  • breast cancer diagnosed in a male relative.
• For women of Ashkenazi Jewish descent:
  • any first-degree relative diagnosed with breast or ovarian cancer; and
  • two second-degree relatives on the same side of the family diagnosed with breast or ovarian cancer.

These family history patterns apply to about 2 percent of adult women in the general population. Women who have none of these family history patterns have a low probability of having a harmful BRCA1 or BRCA2 mutation.