Decoding Your Genetic Risk: Understanding BRCA Gene Testing

What are BRCA genes?

BRCA1 and BRCA2 are genes that produce proteins that help repair damaged DNA. They are named BR for breast and CA for cancer (BRCA). Everyone has two copies of each of these genes; one copy inherited from each parent.

Technically, these genes help repair DNA damage to prevent cancer from developing. But, if there is a hereditary mutation in the gene, then it cannot repair DNA damage to fight off cancer.

The BRCA1 and BRCA2 genes are two of the most common genes known to be associated with an increased risk of cancer, most notably breast cancer and ovarian cancer. People who have inherited this gene mutation also tend to develop cancer at younger ages than people who do not have this variant.

It is important to understand however, that having a BRCA1 or BRCA2 mutation does not mean that a person will develop cancer; it only means that they have an increased risk.

What is the difference between BRCA1 and BRCA2 genes?

BRCA1 and BRCA2 are separate genes that repair DNA damage, but each gene indicates different cancer risks.

BRCA1 mutations are associated with the following compared to BRCA2:

Slightly higher breast cancer risks
Significantly higher ovarian cancer risk

BRCA2 mutations are associated with the following compared to BRCA1:

Slightly higher male breast cancer risk
Slightly higher prostate cancer risk
Slightly higher pancreatic cancer risk
Slightly higher melanoma risk

Why are BRCA genes commonly associated with an increased risk for breast cancer?

An inherited mutated copy of BRCA1 or BRCA2 from a parent means you have a higher risk for breast cancer. Women with a mutated BRCA gene have a 45% to 65% risk of getting breast cancer by age 70, compared to about 13% in the general population. By age 80, a woman with a BRCA1 or BRCA2 gene mutation has up to an 80% chance of being diagnosed with breast cancer.

Are there other genes that increase the risk of breast cancer?

While BRCA1 and BRCA2 are well-known genes, others can also increase the risk of breast cancer. According to the National Breast Cancer Foundation (NBCF), there are other gene mutations that are known to increase breast cancer risk. These include:

PALB2: After BRCA1 and BRCA2, PALB2 is currently the third most prevalent breast cancer gene.

CHEK2: A mutated CHEK2 gene doubles the risk of breast cancer in women. In men, it makes male breast cancer 10 times more likely to occur.

CDH1: A mutation in the CDH1 gene can increase the risk of forming lobular breast cancer, or cancer that begins in the breast’s milk-producing lobules.

PTEN: Can cause a rare disorder known as Cowden Syndrome (CS), which can increase the risk of breast cancer and many other types of cancer.

STK11: Carries an increased risk for multiple types of cancer, including breast cancer.

Keep in mind that having a normal copy of these genes lowers your breast cancer risk. The risk only rises if the gene is mutated and fails to prevent cancer.

The NBCF reports that there are also several other genes, including ATM, BARD1, BRIP1, CASP8, CTLA4, CYP19A1, FGFR2, H19, LSP1, MAP3K1, MRE11A, NBN, RAD51, and TERT, that are thought to also increase the risk of developing breast cancer when they carry a mutation.

“While BRCA testing can provide vital information about your own health risks, it can also supply your family with valuable knowledge that can help to protect the generations that follow.”

Jana Deitch, MD, Chief for Breast Surgery at Catholic Health and Director of the Breast Health Program at St. Catherine of Siena Hospital

How does the BRCA test work?

Genetic counseling is the first step of the process.

Speak with your physician about genetic counseling, especially if you have a family history of breast cancer. Even if you do not have a BRCA or other breast cancer gene mutation, a family history of related cancers can mean cancer risks for you.

For example, a first-degree relative (mother, sister or daughter) diagnosed with breast cancer nearly doubles a person’s risk, and two first-degree relatives with breast cancer increase the risk three-fold.

What is the genetic counseling process?

A genetic counselor will meet with you to discuss the following:

Your health history, including lifestyle and environmental conditions.
Your family tree—dating back three generations. Learning and understanding your family history in preparation for this appointment is important.
If you do not know your family history, your genetic counselor will discuss other options to learn if you carry a genetic variant that increases the risk for cancer.

You will provide a sample of blood or saliva that gets tested for genetic mutations. Your genetic counselor will discuss the results and advise you on the next steps.

You should meet with your genetic counselor every three to five years to update your medical record and family health history.

If I have a BRCA mutation, does that mean I will get breast cancer?

No. Although your risk increases, there is no guarantee you will develop breast cancer. Other factors like lifestyle and environment can also increase cancer risk.

Your genetic counselor and healthcare provider will discuss next steps and can also provide suggestions for how you can help to reduce your risk. Keeping up with your annual OBGYN appointments and scheduling your annual mammogram is vital to detecting breast cancer at an early stage when it is most treatable.

Learn more about the genetic counseling and breast cancer services at Catholic Health.