Genetics and
|
Genetics and
|
Young adults with breast cancer often ask, “Why did this happen to me?” Some find the answer in a family history of cancer, which is the strongest risk factor for developing breast cancer at a young age.
While some risk factors for breast cancer have been identified, such as radiation exposure or certain reproductive factors, these don't explain why any given patient develops breast cancer. A small proportion of patients have an inherited gene mutation that could place them at a higher risk of developing breast cancer. For most people though, there is no clear answer. Younger adults are at much lower risk of developing breast cancer than older adults, but it is diagnosed in those of all ages. Learn more about risk factors for breast cancer.
|
Family history
The biggest risk factor for developing breast cancer at a young age is family history. This is especially true if a close relative (mother, father, sister, daughter) had it at a young age. Overall, about 15% to 20% of all breast cancers seem to have a family link. Family history matters because your cells contain two sets of chromosomes (protein genes and DNA organized in a specific order). You inherit one set of 23 chromosomes from your mother and the other set from your father. Genetic factors that increase risk of certain diseases may be passed from generation to generation in this way. Two genes in particular increase your risk of breast and ovarian cancer if they mutate (change). These genes are called BRCA1 and BRCA2, and they are found on chromosomes 13 and 17, as shown in the image below. |
Around 10% of young adults with breast cancer have an inherited BRCA1 or BRCA2 gene mutation. Certain BRCA1 and BRCA2 mutations can give adults a 50% to 85% chance of developing breast cancer in their lifetime, as well as a higher risk of ovarian cancer.
People more likely to carry a BRCA1 or BRCA2 mutation include those who:
|
Genetic counseling and testing
Knowing whether or not you have a genetic mutation may influence your treatment decisions. This is because these mutations increase your chances of getting new breast cancer or ovarian cancer in the future. Your doctor can refer you to a genetics counselor who can help you sort through all the issues and options. In general, all young adults with breast cancer should consider testing for BRCA1 or BRCA2 mutations. You might also choose to be tested for other genetic disorders that increase risk. Sometimes “panel” testing may be recommended, which tests for rare changes in a number of genes, including BRCA1 and BRCA2. Your doctor or a genetic counselor can help you decide which, if any, tests are right for you. If you have genetic mutations or other risk factors, you're at higher risk of new breast cancer forming in any breast tissue that remains after surgery. For those who keep their breasts, doctors recommend additional screening with breast MRIs on the remaining tissue. Some people in this situation also take tamoxifen (a hormone drug used to treat breast cancer) to reduce their risk of new primary breast cancer. Others choose to have additional surgery such as:
Genetic information may also be important to other members of your family. If you have a genetic mutation, close blood relatives (mother, father, sisters, brothers, children) are at increased risk of having one, too. Talk with your doctor about whether or not genetic testing is right for you, and if so, when it should be done. You may want to have testing done while you’re making early treatment decisions or further along in your treatment. You can also visit Dana-Farber’s Cancer Genetics and Prevention Program page. |
FORCE
(Facing Our Risk of Cancer Empowered). A national nonprofit organization devoted to hereditary breast and ovarian cancer. Provides support, education, and advocacy for people with a BRCA mutation or a family history of cancer. Services are available via a helpline and in person in many states and one UK location. |
MedlinePlus
Brought to you by the National Institute of Health’s National Library of Medicine. Provides consumer-friendly information about the effects of genetic variations on human health |