Genetic Testing for Breast Cancer: How and Why to Get Tested
BRCA1 and BRCA2 are tumor suppressor genes that play a role in protecting from breast and ovarian cancer. As a result, women who have inherited mutations in the BRCA1 or BRCA2 gene are at an increased risk of developing certain cancers, including breast cancer and ovarian cancer. Men who carry a mutation in one of these genes are at an increased risk of developing breast cancer and prostate cancer. In addition to BRCA1 and BRCA2, there are a number of other genes that can impact the risk of breast cancer. Fortunately, there is testing available that can evaluate for mutations in BRCA1/2 and other breast cancer susceptibility genes.
BRCA Gene & Breast Cancer
What is the BRCA test?
Currently, BRCA testing is most often performed via a multigene panel. Multigene panel testing is genetic testing that can be performed on a blood sample, and checks for mutations in multiple genes simultaneously, including BRCA1/2. BRCA gene mutations are the most common cause of hereditary breast and ovarian cancers. Approximately 5-10% of all breast cancers and 10-15% of all ovarian cancers are related to BRCA mutations.
Medical risks associated with the BRCA test include typical risks of blood draw. This can include bleeding, bruising, some people may feel dizzy or lightheaded for a short time, and there may be a very low risk of infection with a blood draw.
Knowing your genetic status can affect you emotionally. This may include feelings of anxiety, anger or depression if your results indicate you are at a higher risk of developing cancer. You may also have concerns about possible insurance discrimination if you have a positive genetic test result. However, there is a federal law, the Genetic Information Nondiscrimination Act, that protects from health insurance and employment discrimination based on genetic test results.
Who should have the BRCA test?
Harmful BRCA1 and BRCA2 gene mutations are relatively rare. However, you may choose to have the BRCA test if you have a personal or family history of early onset breast cancer, ovarian cancer, pancreatic cancer, or high-grade prostate cancer. When BRCA testing is recommended based on personal or family history, insurance companies most often cover the test. There are benefits to having testing. When a mutation is identified, increased screening and risk-reducing procedures can be offered to address the increased risk.
What do BRCA test results mean?
It typically takes 2-4 weeks to get your BRCA test results, and it is important to discuss the results with your doctor and/or genetic counselor to be sure you understand what they mean.
The BRCA test shows mutations in the BRCA1 or BRCA2 genes. When performed as a part of a multigene panel, mutations in other genes may also be detected. There are three types of results that can come back with BRCA testing: positive, negative, and a variant of uncertain significance.
- A positive result indicates you have a known pathogenic (harmful) mutation in the BRCA1 or BRCA2 gene. This means you have a higher risk of getting certain cancers. However, not all people with a mutation will get cancer.
- A negative result means you likely do not have a mutation of BRCA1 or BRCA2. But it does not mean that you will never get cancer.
- A variant of uncertain significance is a change in a gene that may or may not affect the function of the gene. Variants of uncertain significance are frequently reported with multigene panel testing, given the number of genes being evaluated and the presence of genetic variation in the population. When a variant is identified it is not recommended that any unaffected relatives be tested for the variant, and this result is not clinically actionable.
In talking with your healthcare provider you can decide what action if any, you should take based on your BRCA test results.