NARRATOR: Understanding your family history of cancer is important to understanding your own risk.
About 5 to 10 in 100 breast cancers are caused by a single gene and may be hereditary.
We receive a set of genes from each of our parents. These genes are like instructions telling our body how to build cells.
The most commonly affected genes in hereditary breast cancer are the breast cancer 1 and breast cancer 2 genes, called BRCA1 and BRCA2. Normally, these genes prevent cancer cells from growing.
But sometimes they mutate and don’t work properly, which can lead to cancer.
Everyone has the BRCA1 and BRCA2 genes, but only about 1 in 400 people in the United States have a mutation in either gene.
If one of your parents carries a BRCA gene mutation, you have a 1 in 2 chance of having the same mutation.
Not everyone with a BRCA gene mutation will get breast cancer. But these mutations increase your risk, especially of developing breast cancer at a younger age.
Other genetic mutations can also increase your risk of breast cancer, but they don’t seem to increase risk as much as BRCA mutations.
Even in families with no known genetic mutations, there may still be a history of cancer.
These cases could be caused by environmental factors, such as exposure to chemicals or a genetic mutation that has not yet been discovered.
If your family has a history of breast or ovarian cancer, you and your family members are more likely to have a BRCA1 or BRCA2 mutation.
This information helps you understand your risks of developing breast cancer.
Some groups are at higher risk for BRCA gene mutations than others, such as Ashkenazi Jewish women and Latinas.
A genetic counselor can help you understand what your family history means for your personal risk.
Even though you can’t change your genes, you can reduce your risk of developing breast cancer.
Lifestyle choices, such as limiting alcohol consumption, maintaining a healthy weight, and exercising regularly, have been shown to make a difference.
Although it’s not easy to talk about breast cancer with your family, it’s important. The more you know about your genetic history, the more you can do to manage your risk.
This resource was created with support from Merck.
