Is Breast Cancer Hereditary?
Up to 10% of breast cancers are thought to be linked to genetic changes inherited from a parent. That’s why breast cancer sometimes seems to run in families.
Inheriting a genetic change, or mutation, linked to breast cancer doesn’t mean you’ll definitely be diagnosed with breast cancer. It means you have a higher-than-average risk of developing the disease.
What is a gene mutation?
Think of your genes (short segments of DNA) as an instruction manual for your cells. If something changes in the instruction manual (for example, a typographical error), mistakes may happen (for example, the cell might start to behave oddly). In any one person, if there is an error in a gene, that same mistake will appear in all the cells that contain the same gene. This is like having lots of copies of an instruction manual in which all the copies have the same typographical error.
Some genetic changes are harmless, but others can cause disease or other health issues. Genetic changes that negatively affect health are called mutations. If the mutation is passed down from parent to child, it is called an inherited genetic mutation.
Genetic changes that happen over the course of a lifetime, as a result of the natural aging process or exposure to chemicals in the environment, are called somatic alterations. Somatic alterations are acquired in a cell or cells. They're not present at birth and can't be passed down to a child.
How do I know if I have a genetic mutation?
Genetic testing can determine if you have inherited a genetic mutation linked to a higher risk of breast cancer. Your doctor or a genetic counselor can help you decide which type of genetic test is right for you based on your personal or family history of breast cancer and other cancers.
You may have a genetic mutation linked to breast cancer if:
You or a family member were diagnosed with breast cancer younger than age 50 or were diagnosed with two separate primary breast cancers.
You or a family member were diagnosed with triple-negative breast cancer at any age.
You or a family member were diagnosed with ovarian, pancreatic, or high-risk prostate cancer.
You are a man who has been diagnosed with breast cancer or a man in your family has been diagnosed with breast cancer.
You are of Ashkenazi Jewish (Eastern European) heritage.
More than one of your blood relatives — on either your mother's or father's side of the family — was diagnosed with breast cancer at any age.
There is a known breast cancer genetic mutation in your family.
If one family member has a genetic mutation linked to breast cancer, it does not mean that all family members will have it.
Inherited genetic mutations linked to breast cancer
Most inherited cases of breast cancer are associated with mutations in two genes: BRCA1 (BReast CAncer gene one) and BRCA2 (BReast CAncer gene two). Mutations in these genes also increase the risk of ovarian cancer, pancreatic cancer, prostate cancer, and melanoma (skin cancer).
Other inherited genetic mutations linked to a higher risk of developing breast cancer include:
Research suggests that women with a PALB2 mutation have a 53% risk of developing breast cancer by age 80. A PALB2 mutation also increases the risk of pancreatic cancer in both women and men.
Inherited mutations in the PTEN gene cause a very rare condition called Cowden syndrome, in which people have a higher risk of both benign (not cancer) and cancerous breast tumors, as well as growths in the digestive tract, thyroid, uterus, and ovaries.
Inherited mutations in the TP53 gene cause Li-Fraumeni syndrome, a rare condition in which people can develop cancers throughout their lifetimes, starting in childhood. The main types of cancer diagnosed in people with Li-Fraumeni syndrome are soft tissue cancers, adrenal gland cancer, leukemia, brain cancer, and breast cancer.
Research suggests that ATM mutation carriers have double the average risk of developing breast cancer.
Inherited mutations in the CDH1 gene cause a condition known as hereditary diffuse gastric cancer. In addition to the increased risk for gastric cancer, women with a CDH1 mutation also have a higher risk developing breast cancer.
The location of the mutation in the CHEK2 gene affects the level of risk conferred by the mutation. Truncating CHEK2 mutations, which means the mutation shortens the gene's coding sequence. doubles the average risk of breast cancer and can also increase the risk for prostate and colon cancer. Mutations in other locations only slightly increase breast cancer risk, so the results need to be interpreted carefully.
Inherited mutations in the STK11 gene causes Peutz-Jeghers syndrome, a rare disorder in which people tend to develop a type of polyp, called a hamartomatous polyp, mostly in the small intestine but also in the stomach and colon. In addition to gastrointestinal cancers, people with Peutz-Jeghers syndrome are also at higher risk of breast cancer, lung cancer, and ovarian tumors.
Inherited mutations in either the RAD51C or RAD51D gene moderately increase breast cancer risk, particularly the risk of triple-negative breast cancer. Both gene mutations also increase the risk of ovarian cancer.
Inherited mutations in the BARD1 gene moderately up breast cancer risk, particularly triple-negative breast cancer.
What this means for you
If you do test positive for a genetic mutation linked to breast cancer, there are steps you can take to keep your risk as low as possible.
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— Last updated on February 28, 2025 at 9:00 PM