If you carry BRCA1 or BRCA2 gene mutations, you may be at an increased risk of developing certain types of cancers — but it’s important to understand that cancer genetics are complex and other factors influence risk as well.
Depending on certain factors like family history, it may be advisable to seek proper genetic counseling to be aware of your risks and steps you can take to help prevent cancer. Together with your care team, you can empower yourself to make the decisions that are right for you.
Here, Huma Q. Rana, MD, clinical director for Dana-Farber’s Center for Cancer Genetics and Prevention, explains the BRCA1 and BRCA2 genes, the risks, and genetic counseling services.
What are BRCA1 and BRCA2 gene mutations? How do they relate to cancer risk?
BRCA1 and BRCA2 are genes that suppress tumors by producing proteins that repair DNA damage and keep cell growth stable. Gene mutations can either be:
- Inherited
- Categorized as a somatic mutation (meaning it occurs by chance)
When either gene is mutated, its primary function is altered (or interrupted), which can lead to unrepaired DNA damage or other alterations, increasing one’s risk of developing cancer.
Does having the BRCA1 or BRCA2 gene mutation mean I will develop cancer?
No, but it increases your risk of cancer. BRCA mutations give you an 8 to 10-fold increased risk of breast cancer; for ovarian cancer, it increases by about 20-fold, and melanoma risk increases by two-fold. Some people with BRCA mutations can go their whole lives without developing cancer—and the same is true for their families.
What cancers can the BRCA mutation put me at risk for?
BRCA1 and BRCA2 mutations can put you at a lifetime risk for several cancers. For women, this includes breast, ovarian, fallopian tube, and peritoneal (lining of abdominal, uterus, bladder, and rectum) cancer. Of these cancers, breast and ovarian cancer are the most prevalent for women with BRCA mutations.
BRCA1 and BRCA2 mutations were first identified as part of a syndrome called hereditary breast and ovarian cancer. Women generally have the greatest risk of developing those cancers associated with these kinds of syndromes if they have an inherited mutation in either BRCA1 or BRCA2.
Men who carry the BRCA2 gene mutation are also at an increased risk of aggressive prostate cancers and male breast cancer. There is moderate increase in risk for melanoma and pancreatic cancer irrespective of sex.
Should I seek genetic counseling and testing?
Whether or not you need genetic counseling depends on several factors. Currently, there are a number of targeted cancer treatments that rely on genetic test results. For individuals without cancer, your family history of cancers or positive genetic test results for BRCA mutations 1 or 2 would prompt testing. This information will allow doctors to determine your risk through screening.
If a family member had one of the mutated BRCA genes and was diagnosed with cancer, when should I be tested?
It depends on when the information would impact your care. This differs by gender and stage of life. For women, if positive for a BRCA mutation, breast cancer screening begins at age 25. This is based on the fact that women with BRCA1 and BRCA2 mutations have an increased risk of developing breast cancers at an earlier age of onset than women in the general population.
For men with BRCA mutations, this information impacts medical care around age 35. The test results can inform other screening tests in the child-bearing population at the time of family planning.
What should I bring to genetic counseling services?
If you or any of your family members has had cancer, it is helpful to bring your pathology reports or any genetic test results to your counseling visit. If you haven’t been diagnosed with cancer, but the cancer runs in your family, you should find out the type of cancer and ages family members were diagnosed. Your relatives’ pathology reports, as well as copies of their genetic testing results, are incredibly helpful. If you don’t have test results but know that certain relatives were diagnosed with cancer, fill out a Family History Form before your visit.
What can I expect at my appointment?
Your genetic counselor will look at your detailed family history to evaluate if you have any inherited predisposition to cancer. Testing options will be explained depending on the gene(s) that are associated with cancer risk or other medical issues. Insurance issues (coverage, protections), familial implications, and confidentiality will be discussed, along with cost, and logistics of testing.
What can I do to lower my risk of cancer if I have the BRCA1 or 2 mutation?
To help lower your risk of developing cancer, it is recommended that everyone, including individuals with a BRCA1 or 2 mutation do the following:
- Engage in 3-5 hours of cardiovascular activity per week
- Don’t smoke
- Limit their alcohol intake to ideally less than 3-4 alcoholic beverages per week
- Limit red meat consumption to no more than 2 servings per week
- Use sun protection