Breast Cancer & Genetics

If you’ve paid attention to breast cancer awareness campaigns, it’s likely that you know that the average woman in the United States has a 1 in 8 chance of developing breast cancer. But did you also know that roughly 10% of all cases of breast cancer can be attributed to heredity factors?


By Julianne Hale



BreastCancerGenetics2BRCA1 and BRCA2

In the mid-‘90s the medical community discovered key genetic indicators that could help identify the risk of breast cancer: mutations in BRCA1 and BRCA2.

The BRCA1 and BRCA2 genes are in fact found in every human being – their function is to repair cell damage in the breast and keep it growing normally. However, in some individuals the genes contain abnormalities that are passed down from generation to generation.

“If a person tests positive for a mutation in either gene, his or her risk for breast cancer goes up significantly,” explains Madison Thomason, a certified genetic counselor with Erlanger Health System. “For women who have a mutation in either gene, there is up to an 87% chance for breast cancer during their lifetime. Men with a BRCA1 or BRCA2 mutation may have up to a 7% chance for male breast cancer.”

If a mutation in either of these genes is found, it also puts the person at a higher risk for certain other cancers. “For women, one of these is ovarian cancer,” says Thomason. “Depending on which gene carries a mutation, a woman may have up to a 44% lifetime chance of having ovarian cancer. Men who have a BRCA1 or BRCA2 mutation are at a higher risk for early onset prostate cancer, while a person of either gender who tests positive may have a higher risk for melanoma and pancreatic cancer.”


Genetic Risk Factors

If your mother, grandmother, or aunt has had breast cancer that does not necessarily mean you will develop the disease. However, it may mean that your risk for breast cancer is increased and that you may need to be more proactive about screenings. It may also be appropriate for you to consider genetic testing.

If any of the following risk factors are present in you or your family, it might be time to talk to your doctor about the possibility of genetic testing.

A diagnosis of breast cancer before the age of 50 in you or a blood relative (grandmother, mother, sister, or aunt) on either side of the family.

Cancer in both breasts.

Ovarian cancer.

Multiple cases of breast cancer within your family.

Ashkenazi Jewish heritage.

A male with breast cancer.

Thomason says that it’s very important to understand that BRCA1 or BRCA2 mutations can be inherited from either side of the family. “A lot of times people don’t understand that you can receive the gene abnormalities from your mother’s side or your father’s side,” she says. “This means that even men may need to be tested too.”


Madison Thomason, MS Certified Genetic Counselor, Erlanger Health System

Madison Thomason, MS Certified Genetic Counselor, Erlanger Health System

Testing, Testing, 1, 2, 3

Once you’ve gone through your family history and determined that there are one or more risk factors present, you should speak with your doctor about whether or not genetic testing is something you should consider. Genetic testing for a BRCA1 or BRCA2 mutation is not appropriate for everyone. Knowing whether your body has a BRCA1 or BRCA2 mutation may help you determine your risk for developing breast cancer long before your health is ever in jeopardy, but this information comes at a cost, both emotionally and financially. This is where a genetic counselor comes into play.

The Centers for Disease Control and Prevention (CDC) defines genetic counselors as “specially trained professionals that help people learn about genetic conditions, find out their chances of being affected by or having a child or other family member with a genetic condition, and make informed decisions about testing and treatment.”

The genetic counselor will gather detailed family and medical histories, discuss the risks and benefits of genetic testing, and outline your options. If your relative that has been diagnosed with cancer is alive and willing to get tested, it is recommended that they be tested first.  If it comes back positive, then you and other relatives will likely need to be tested for the specific genetic mutation. If the test comes back negative, this does not necessarily mean that you do not have an increased risk for breast cancer, and it would be best for you to speak with a genetic counselor about your risks.

If you decide to go ahead with testing, you will sign an informed consent. This is a critical step because it signifies that you understand the risks and benefits associated with the test and consent to having it done.


BreastCancerGenetics4Test Results: Moving On

While there is no health risk to having the genetic test done, the emotional toll of the results can be high, as each possible outcome – positive, negative or inconclusive – carries with it a certain emotional baggage. For example, while a positive result can be empowering, it can also make you feel anxious, guilty, depressed and angry. With a negative result may come feelings of both relief and survivor guilt, while an inconclusive result can lead to frustration and anxiety.

Your genetic counselor can help you navigate the emotions that come with your test results – and also provide you with the specifics of what each test result means moving forward. Here is a brief summary:

A positive result means that you have inherited a harmful mutation in BRCA1 or BRCA2 and are at an increased risk for developing breast and ovarian cancer. This information, while scary, does not mean that you have cancer or will definitely develop it, but it can be used to empower you to protect your health.

A negative result means that you have not inherited a known harmful mutation in the BRCA1 or BRCA2 genes. However, this does not necessarily mean that your breast cancer risk is the same as that of the general population. Your family history alone may still suggest that you have an increased risk for breast cancer, and you should follow a cancer screening plan upon which you and your doctors agree.

An inconclusive result means that a change in a gene(s) was found, but it is not clear whether or not this change causes a higher risk for cancer. These kinds of results aren’t uncommon. A genetic counselor will help you understand this result and figure out how to move forward.


Peace of Mind and Proactivity

If a family history of breast cancer is a concern for you, you may want to speak with your doctor or a genetic counselor about genetic testing. However, it is important to remember that the vast majority of breast cancer cases occur in women with no family history of the disease, so, regardless of whether testing is a consideration, it is critical to undergo regular screenings and be proactive about breast health.