BRCA1 and BRCA2 are human genes that produce tumor suppressor proteins. These proteins help repair damaged DNA and, therefore, play a role in ensuring the stability of the cell’s genetic material. When either of these genes is mutated, or altered, 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 additional 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. The effects of mutations in BRCA1 andBRCA2 are seen even when a person’s second copy of the gene is normal.
The BRCA gene test is a blood test that uses DNA analysis to identify harmful changes (mutations) in either one of the two breast cancer susceptibility genes — BRCA1 and BRCA2.
Women who have inherited mutations in these genes are at an increased risk of developing breast cancer and ovarian cancer compared with the general population.
The BRCA gene test is offered only to people who are likely to have an inherited mutation based on personal or family history, or who have a specific type of breast cancer. The BRCA gene test isn’t routinely performed on women at average risk of breast and ovarian cancers.
A BRCA gene test determines whether you carry an inherited BRCA mutation. If you do, your result is positive and your doctor can help you understand your cancer risk. If you don’t have a mutation, this is considered a negative result. However, you may learn you have a gene variant that doctors aren’t sure about. It may or may not be associated with an increased risk of breast and ovarian cancer. This result is known as a variant of uncertain significance.
Most people considering genetic testing undergo genetic counseling, which can help you understand what the results could mean for your health and help you decide whether genetic testing is right for you.
Source : National Cancer Institute