Inherited genetic mutations can increase a woman’s risk of developing breast cancer. For instance, a mutation in two of the better-understood genes linked to a substantial increased risk of breast cancer, the BRCA1 and BRCA2 genes, account for up to:
- 10 percent of all breast cancers.
- 50 percent of hereditary breast cancers (caused by inherited genetic mutations).
Women with a strong family history of breast cancer should take time to learn how genetic testing is appropriate for them. It is important to remember that risk can be passed down from either your father or mother. A detailed knowledge of the medical history of your relatives can be extremely helpful.
Graphic courtesy of Ambry Genetics.
Other mutations can increase cancer risk. These include ATM, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, MRE11A, MUTYH, NBN, NF1, PALB2, PTEN, RAD50, RAD51C, RAD51D and TP53.
Many of these genes are responsible for cell regulation and tumor suppression such that when they are not working properly (mutated) they allow cells to travel down the cancer pathway.
If one is found to have a gene mutation associated with an increased risk of breast cancer it is strongly recommend those women consult with a breast health specialist. This consult can empower women to learn more about ways to reduce their risk of a cancer diagnosis. The most powerful outcome of identifying these genetic problems is having an opportunity to prevent a potential cancer.
How do mutations in the BRCA1 and BRCA2 genes affect breast cancer risk?
The BRCA1 and BRCA2 genes produce a type of protein that helps to suppress the growth of tumors by repairing damage to DNA. When specific mutations to one of these genes occur, they do not properly function. This can increase risk for developing breast cancer, as well as other types of cancer like ovarian cancer.
According to some estimates, up to 65 percent of women with a BRCA1 mutation and up to 45 percent of women with a BRCA2 mutation will develop breast cancer by the age of 70.
Genetic Testing Options for Women
Several different tests are currently available to identify genetic mutations
- Single-panel genetic testing only looking at individual genes.
- Multi-panel genetic testing allows the evaluation of a large group of genes linked to increased cancer risk.
In 2013, the United States Preventive Services Task Force (USPSTF) issued recommendations regarding genetic testing in suspected carriers of BRCA1 or BRCA2 gene mutations. These recommendations urged physicians to use one of several available screening tools in women with a family history of breast or ovarian cancer. There are several companies performing genetic testing
If screening results are positive (there is a change in the gene that affects its ability to perform its job), physicians should recommend patients for genetic counseling. Genetic counseling is generally conducted prior to and following any type of genetic testing. This consists of a hereditary cancer risk assessment and a discussion of:
- Implications of test results, whether positive or negative.
- Benefits and psychological risks to genetic testing.
- How offspring might be affected by results.
How does genetic testing work and how much does it cost?
To test genetic mutations, a blood sample is taken and sent to a laboratory for analysis. As genetic testing for breast cancer risk becomes more widespread, there are more and more laboratories offering this service.
These tests typically cost anywhere from several hundred to several thousand dollars. Many insurance plans now cover the cost for high-risk women.
What happens after genetic testing genetic mutations?
If the test results are negative, indicating the patient is does not have a change in the gene affecting its function, it does not necessarily mean that she is no longer at increased risk for breast cancer.
The relationships between genetics, family history and breast cancer risk are still not fully understood. Over time, other genes may be identified to be causative and additional testing may be recommended
If a patient receives positive test results, there are several options available. All of these options should be discussed at length with a breast care specialist who is trained in high-risk follow-up and can review the pros and cons.
- A woman can choose to have a mastectomy (removal of all of the visible breast tissue) to reduce her risk of developing breast cancer or
- Begin screening earlier to increase the chances of catching a breast cancer before it has grown too much.
- Women who choose not to have surgery can also opt to receive a hormone blocking agent that can act to reduce the possibility of cancerous changes
Whether results are negative or positive, careful genetic counseling following testing can help women to decide how best to proceed with their breast health needs. What is the correct path for one patient may not be the best choice for another. These are very individual decisions.
Through better understanding of genetics we can recommend improved technologies to detect, treat and prevent breast cancer in women with BRCA1, BRCA2 and other genetic mutations. As knowledge continues to evolve, genetic testing and counseling and prevention strategies will continue to be refined.