Cancer Risks Associated with the BRCA Gene

BRCA genes are responsible for generating proteins to help suppress and repair damage to DNA. This is an important task because damaged DNA can increase your risk of developing certain cancers.

There are two types of BRCA genes:

• Breast Cancer Gene 1 (BRCA1)
• Breast Cancer Gene 2 (BRCA2)

Sometimes these genes may undergo mutations, which can suppress their ability to fight potential tumor development.

BRCA gene mutations

You have two copies of both BRCA genes from each of your parents. If one or both parents has a BRCA gene mutation, your risk of also having such mutations is also greater.

While the National Cancer Institute (NCI) estimates that BRCA gene mutations affect 1 in 400 people, they also note a higher prevalence in certain ethnic groups. These include those of Ashkenazi Jewish, Icelandic, Norwegian, and Dutch descent.

If you do have a BRCA gene mutation, your risk for certain cancers — especially breast and ovarian cancers — may be greater. However, these mutations may also increase your chances of developing other types of cancer, too.

The only way to know if you have a BRCA mutation is to undergo genetic testing. This step is especially important if you know one of your parents has this type of gene mutation.

BRCA gene mutations are primarily known for increasing the risk for hereditary breast cancer.

The NCI estimates that 13 percent of women will develop breast cancer at some point in their lifetime. However, 55 to 72 percent of women who inherit the BRCA1 mutation and 45 to 69 percent who inherit the BRCA2 mutation will develop breast cancer by age 70 to 80.

Another risk to consider is contralateral breast cancer. This type of breast cancer affects the opposite breast from the site of the original cancer diagnosis. According to the NCI, this risk increases over time, with a 20 to 30 percent risk after a decade, and 40 to 50 percent after 20 years.

Women who have BRCA variants may also have an increased risk of triple-negative breast cancer (TNBC).

While breast cancer is most common in women over 55 years of age, having BRCA mutations could increase your risk of developing tumors sooner.

Another notable risk associated with BRCA gene mutations include ovarian cancer. According to the American Cancer Society, while less than 2 percent of women develop ovarian cancer, 25 percent of cases are attributed to inherited gene mutations.

The NCI estimates that between 39 and 44 percent of women who have BCRA1 variants will develop this cancer and 11 to 17 percent of women with BCRA2 variants may develop it.

Also, if you’ve already had breast cancer, you may have a greater risk of developing ovarian cancer.

BRCA gene mutations are primarily associated with breast and ovarian cancers in women. However, gene variants may increase the risk of other cancers, too.

These may include the following:

• breast cancers in men
• prostate cancer
• fallopian tube cancer
• primary peritoneal cancer in women, which sometimes spreads to the ovaries
• pancreatic cancer
• acute myeloid leukemia in children

You may consider genetic testing for BRCA variants if you have a personal or family history of certain cancers. This is especially applicable in the case of breast and ovarian cancers.

Even if you already have a cancer diagnosis, genetic testing can help your oncologist determine the right course of treatment.

Your doctor will also likely recommend testing if one of your parents has a known BRCA1 or BRCA2 mutation. Genetic testing for these two variants may be conducted after the age of 18.

Testing for BRCA gene mutations may be done in a lab via a blood or saliva sample. While at-home genetic testing is also available, it’s important to find options that are FDA-approved.

Keep in mind that there’s a risk for false-negative results. This means that the particular test didn’t detect the BCRA gene mutations despite their presence in your body.

A positive test result means you have a “likely pathogenic” or “pathogenic” variant. While you may be at an increased risk of certain cancers, having a BRCA mutation doesn’t automatically mean you’ll get cancer.

Still, having a positive test result can be a powerful tool in helping to mitigate or catch cancer early. For example, your doctor may recommend early screenings.

Some people also choose to have more aggressive treatments to prevent cancer. Examples include preventive mastectomies, chemopreventive drugs, or ovarian/fallopian tube removal.

If you already have a cancer diagnosis and obtain a positive BRCA mutation test result, this can determine the right course of treatment. Poly-ADP ribose polymerase (PARP) inhibitors may be especially helpful. These cancer drugs encourage DNA repair in the presence of BRCA variants.

Finally, if you test negative, your doctor may still want to keep a watchful eye if you have a family history of risk factors for cancer. This may include follow-up genetic testing in the case of false-negative results.