There are a lot of things we can control in our lives, but our inherited genes are not one of them. That’s why people start to ask questions about a possible genetic link when someone in their family is diagnosed with cancer. While most cancers are not related to an inherited genetic mutation, there are some that have a link to our genes passed down to us. This is especially a concern when family members are diagnosed with breast cancer, ovarian cancer, or prostate cancer.
While this may not be something you think about when your family is healthy, it often comes to mind when there is a new cancer diagnosis in the family.
Genes vs the Environment: What Is the Cause of Cancer?
Not all cancers are caused by a genetic mutation passed through the generations. In fact, most are not. Most cancers develop based on how your body responds to the environment, your diet and other factors over the years.
When you think of lung cancer, exposure to chemicals in smoke or in the workplace are what generally come to mind in regard to the cause. We know that skin cancer is usually caused by a mutation in the cells due to too much ultraviolet light exposure. We’ve learned all of this through extensive research over decades.
In recent years we have gained a better understanding of our DNA and genetics and how that can play a role in whether you develop cancer in your lifetime. Some gene mutations can make you more likely to develop cancer in the future. But not everyone has a known genetic mutation related to cancer.
Although most genetic changes are minor, approximately 1 out of every 500 women inherit a mutated BRCA1 or BRCA2 gene that can increase the risk of a woman developing breast and/or ovarian cancers in their lifetimes.
How the BRCA Gene Mutation Increases Your Risk of Ovarian Cancer
The common gene mutation related to ovarian cancer is in the BRCA1 or BRCA2 gene. A woman with this mutation present has an increased chance of developing ovarian cancer. Among the general population, only about 1% of women develop ovarian cancer. However, if you have inherited the BRCA gene mutation, that likelihood goes up. Among women with the BRCA1 mutation, between 39% and 44% will develop ovarian cancer. The BRCA2 gene does not increase your risk as much with 11%–17% of developing ovarian cancer by 70–80 years of age (2–4).
Why does a mutation to the BRCA gene make you more likely to develop cancer?
When these genes mutate, the body loses its ability to repair DNA damage as effectively as it would naturally throughout a person’s lifetime. In normal cells, the BRCA genes make proteins that repair damaged DNA. Mutated versions of these genes can lead to abnormal cell growth.
How are BRCA gene mutations identified?
Mutations in the BRCA1 and BRCA2 genes are often identified through standard gene sequencing testing in blood or saliva. Additional tests can be run to identify a type of mutation called rearrangements, meaning duplications or deletions that can increase cancer risk. It’s important to remember that having a genetic mutation of the BRCA1 or BRCA2 gene does not mean you’re definitely going to develop ovarian cancer or breast cancer. These tests simply indicate whether an increased risk is present. Identifying an increased risk makes it possible to take preventive actions and you can be monitored more closely than someone of average risk.
How to Get a Genetic Test for the BRCA Gene Mutations
If you have a family member, or even a few, who have developed breast, ovarian or prostate cancer you may want to consider genetic testing to see if you have the BRCA gene mutation. The gene can be passed down from your mother or your father’s side of the family.
If a family member tests positive for the mutation, there is a chance you also have it, and you would likely qualify for testing. Meeting with a genetic counselor can help you decide if you and your family would benefit from genetic testing for cancer.
Once testing is complete, the genetic counselor will review the results and determine what they mean. If a BRCA gene mutation is present, you may want to notify family members so they can also be tested. There’s no guarantee that the gene has passed to everyone; therefore, individual testing would be needed.
Be sensitive when telling the family because this can be scary for them, especially before they’ve had a chance to learn more and talk to the genetic counselor. It will be up to them to decide if they’d like to be tested for the mutation.
What if Other Types of Cancer Seem to Run in Our Family?
There are some other types of cancer related to the BRCA gene mutation. The most well-known is breast cancer. But more research has shown that it can also be related to fallopian tube cancer, peritoneal cancer, male breast cancer, prostate cancer and even pancreatic cancer, although the risk increase is low.
You might consider consulting with a genetic counselor if you or a family member meet any of the following criteria:
Personal history of two or more types of cancer
Personal history of breast cancer diagnosis before the age of 45
A breast cancer diagnosis in two or more family members at a young age
A history of one or more family members diagnosed with breast cancer before age 50
A family member diagnosed with two or more types of cancer
A family member diagnosed with bilateral breast cancer
A male family member was diagnosed with breast cancer
A relative was diagnosed with a BRCA1 or BRCA2 mutation
Family history of two relatives with prostate or pancreatic cancer
Family history of nonpolyposis colorectal cancer (Lynch syndrome)
An unknown family medical history or limited knowledge of that history
A history of breast, ovarian, or pancreatic cancer in families of Ashkenazi Jewish descent
While you can’t control your genetic makeup, you can be in control of the actions needed to screen for and even prevent cancers caused by BRCA mutation. Talking with your doctor can help determine the best options for you.