BRCA1 and BRCA2 are genes that produce tumor suppressor proteins. These proteins help repair damaged DNA and help ensure the stability of the cell’s genetic material.

When either of these genes is mutated such that its protein product either is not made or does not function correctly, DNA damage may not be repaired properly. As a result, cells are more likely to develop genetic alterations that can lead to cancer.

Specific inherited mutations in BRCA1 and BRCA2 increase the risk of female breast and ovarian cancers, and they have been associated with increased risks of several additional types of cancer.

Together, BRCA1 and BRCA2 mutations account for about 20 to 25 percent of hereditary breast cancers and about 5 to 10 percent of all breast cancers.

In addition, mutations in BRCA1 and BRCA2 account for around 15 percent of ovarian cancers overall.

Breast and ovarian cancers associated with BRCA1 and BRCA2 mutations tend to develop at younger ages than their nonhereditary counterparts.

A harmful BRCA1 or BRCA2 mutation can be inherited from a person’s mother or father. Each child of a parent who carries a mutation in one of these genes has a 50 percent chance (or 1 chance in 2) of inheriting the mutation.