Hereditary Breast Cancer: Identifying Your Risk

Updated 10/5/20

Each year, more than 200,000 women in the U.S. learn they have breast cancer. While most happen by chance, 5 to 10 percent of breast cancer cases are linked to an inherited gene mutation.

How Can Breast Cancer be Inherited?
Hereditary breast cancer is caused by abnormal genes passed from parent to child — from either the mother’s or father’s side.

Genes are made up of DNA, which contain instructions for regulating cell growth. Damage or changes in the DNA can produce the wrong set of instructions, altering normal cell production.

DNA can become damaged or changed as a result of natural aging processes, environmental and lifestyle factors or an inherited genetic mutation. Some DNA changes are harmless, but others can give rise to cancer by allowing cells to grow and divide in an uncontrolled way, forming a tumor.

BRCA1 and BRCA2 Genes
The most common cause of hereditary breast cancer is an inherited genetic mutation in the BRCA1 or BRCA2 gene (BReast CAncer genes 1 and 2).

Despite what their names suggest, these genes don’t cause cancer. Instead, they normally play a role in protecting you from cancer by repairing damaged DNA and keeping breast and other cells from growing uncontrollably.

Because of this, the BRCA genes are actually known as tumor-suppressing genes. In some people, these tumor-suppressing genes don’t function properly because they contain hereditary mutations passed down from parent to child. This can, in turn, lead to the development of cancer.

How Much Does Having a BRCA1 or BRCA2 Gene Mutation Increase Your Risk?
Women with a BRCA1 or BRCA2 mutation face a dramatically increased lifetime risk of breast cancer: 72 percent of women who inherit a BRCA1 mutation and about 69 percent of women who inherit a BRCA2 mutation are likely to develop breast cancer by the age of 80, compared with about 12 percent for women with no inherited genetic risk.

Men with BRCA2 mutations, and to a lesser extent BRCA1 mutations, are also at increased risk of breast cancer and prostate cancer.

Men and women with mutations in BRCA1/BRCA2 may be considered at an increased risk for melanoma and pancreatic cancer as well.

While the risk of breast cancer is higher for those who have a BRCA1 or BRCA2 mutation, increased screening and preventative surgical options have been shown to dramatically reduce the risk of cancer or identify cancer early, when it is most easily treated and cured.

Getting Tested for a Genetic Mutation
Learning about your hereditary risk can go a long way in helping you take the right steps to prevent breast cancer.

A genetic counselor can help you assess your cancer risks and answer any questions you may have. Your counselor can also help determine whether you and your family are likely to have a mutation that make it worth getting tested.

Genetic testing involves a blood or saliva test performed by a specialized laboratory. Testing is usually recommended when you have any of the following:

• A known BRCA1, BRACA2 or other inherited mutation in your family.
• A strong family health history of breast and ovarian cancer, early onset cancers or multiple cancers in a single person.
• A moderate family health history of breast cancer and are of Ashkenazi Jewish or Eastern European descent.
• A personal history of female breast cancer that meets certain criteria such as age at diagnosis, type of cancer and family health history.
• A personal history of ovarian, fallopian tube or primary peritoneal cancer, male breast cancer, pancreatic cancer or prostate cancer.

To make an appointment with genetic counselor, call Rocky Mountain Cancer Centers at 303-930-7872.