August 1, 2018
BRCA genes and Breast Cancer: Should You Be Tested?
A woman’s lifetime risk of developing breast and/or ovarian cancer is greatly increased if she inherits a harmful mutation in the BRCA1 or BRCA2 genes. Because of this, some women choose to get tested to see if they have mutations in these genes. Keep reading to see if you should consider having this test done.
What are the BRCA genes?
BRCA1 and BRCA2 are human genes that create proteins which help repair damaged DNA. If these genes do not work right, they may not repair damaged DNA. As a result, cells may be more likely to develop cancer.
How does this affect breast cancer?
Studies have shown that the BRCA genes specifically play a role in female breast and ovarian cancers. People who have inherited mutations in BRCA1 and BRCA2 tend to develop breast and ovarian cancers at younger ages than people who do not have these mutations. About 12% of women in the general population will develop breast cancer sometime during their lives. By contrast, about 72% of women who inherit a harmful BRCA1 mutation and about 69% of women who inherit a harmful BRCA2 mutation will develop breast cancer by the age of 80.
Are there tests to check for mutated BRCA genes?
Yes, several different tests are available. Some tests look for a specific harmful BRCA1 or BRCA2 gene mutation that has already been identified in another family member. Other tests check for all of the known harmful mutations in both genes. DNA (usually from a blood or saliva sample) is needed for all of these tests. The sample is sent to a laboratory for analysis. It usually takes about a month to get the test results.
Who should get tests done?
Because mutations in these genes are rare, most expects agree that only women who have family members with breast, ovarian, fallopian tube, or peritoneal cancer get checked out to see if they have a family history associated with an increased risk of these harmful gene mutations.
Some things that might indicate that a woman should get tested are:
- Breast cancer diagnosed in a close relative before they’re 50 years old
- Cancer in both breasts in the same woman in the family
- Both breast and ovarian cancers in either the same woman or the same family
- Multiple breast cancers in the family
- Two or more primary types of BRCA1- or BRCA2-related cancers in a single family member
- Cases of male breast cancer
- Ashkenazi Jewish ethnicity
What will the test tell you?
The test will give you one of three results.
Positive: A positive test result indicates that a person has inherited a known harmful mutation in BRCA1 or BRCA2. This doesn’t mean she will get cancer, it just means she has an increased risk of developing certain cancers and should be more diligent about screenings and prevention.
Negative: A negative test result can be more difficult to understand than a positive result. A true negative result happens when the person being tested has a close relative with the BRCA mutation but the tested person does not. This means the tested person definitely does not carry the harmful mutation and cannot pass it on to their children. They have the same risk of cancer as someone in the general population.
If the tested person has a family history that suggests the possibility of having a harmful mutation but the tests didn’t pick up on the mutation in a close relative, a negative result is less clear. It could mean that the tests just don’t pick up on that specific family’s genetic mutation. The likelihood of this is small, but it can happen.
Ambiguous or uncertain result: 10% of women tested receive an uncertain result. That means that the tests find a change in their BRCA genes, but not one that has been associated with cancer. This change could eventually be shown to be associated with cancer, or it could not.
What should you do if you want to be tested?
It’s recommended that people who want this genetic test done talk to a genetic counselor first. A genetic counselor is a health care professional who has a lot of knowledge about cancer genetics.
Genetic counseling covers many aspects of the testing process, including a cancer risk assessment and discussion of the following:
- The appropriateness of genetic testing
- The medical implications of a positive or a negative test result
- The possibility that a test result might not be informative (that is, it might find an alteration whose effect on cancer risk is not known)
- The psychological risks and benefits of genetic test results
- The risk of passing a mutation to children
- Explanation of the specific tests that might be used and the technical accuracy of the tests
Before you consider having any genetic testing done, you should talk to your healthcare provider. He or she will have a better understanding of your personal health and whether or not you should consider undergoing testing. If you do not have a doctor and would like help finding one, call Healthcare Coordination at 865-305-6970 or go online to make an appointment.
If you would like more information about the BRCA tests, or information about breast or ovarian cancer, contact the Health Information Center. The Health Information Center is a library staffed by medical librarians and certified health information specialists. Contact us with any health information needs and we will research, print information and mail or email it to you for free. We also have a large collection of health books covering a variety of topics. If fact, we have several books about breast cancer:
Becoming a library member is free and only requires a picture ID.
The Health Information Center in located on the ground floor the hospital. We have computers, printers, and a quiet place to take a break. We are open the following times:
Mon.-Thurs., 8:30 am-9 pm
Fri., 8:30 am-5 pm
Sat., 9 am-5 pm
Sun. 1 pm-9 pm
Call or stop by and see us today.