BRCA Gene Mutations

Sometimes, changes or “mutations” occur that prevent genes from doing their job properly. Certain mutations in the BRCA genes make cells more likely to divide and change rapidly, which can lead to cancer.

All women have BRCA1 and BRCA2 genes, but only some women have mutations in those genes. About 1 in every 500 women in the United States has a mutation in either her BRCA1 or BRCA2 gene. If either your mother or your father has a BRCA1 or BRCA2 gene mutation, you have a 50% chance of having the same gene mutation.

Some groups are at a higher risk for a BRCA gene mutation than others, including women with Ashkenazi Jewish heritage.

Why BRCA Gene Mutations Matter

Not every woman who has a BRCA1 or BRCA2 gene mutation will get breast or ovarian cancer, but having a gene mutation puts you at an increased risk for these cancers.

• About 50 out of 100 women with a BRCA1 or BRCA2 gene mutation will get breast cancer by the time they turn 70 years old, compared to only 7 out of 100 women in the general United States population.
• About 30 out of 100 women with a BRCA1 or BRCA2 gene mutation will get ovarian cancer by the time they turn 70 years old, compared to fewer than 1 out of 100 women in the general U.S. population.

If you have a family history of breast cancer or inherited changes in your BRCA1 and BRCA2 genes, you may have a higher breast cancer risk. Talk to your doctor about these ways of reducing your risk—

• Antiestrogens or other medicines that block or decrease estrogen in your body.
• Surgery to reduce your risk of breast cancer—
  • Prophylactic (preventive) mastectomy (removal of breast tissue).
  • Prophylactic (preventive) salpingo-oophorectomy (removal of the ovaries and fallopian tubes).

It is important that you know your family history and talk to your doctor about screening and other ways you can lower your risk. For more information about breast cancer prevention, visit Breast Cancer (PDQ): Prevention.