Genetic Mutations in BRCA1 and BRCA2: To Test Or Not To Test?

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When we discuss testing for BRCA1 and BRCA2, it means that a blood sample will be collected to test if you carry a mutation in the BRCA1 and/or BRCA2 genes. The decision of whether to get tested for mutations in these genes is extremely personal. However, before jumping into whether or not to test, it is important to better understand the genes and what it means to carry a mutation in either or both of them.

Most cancers are not hereditary but instead result from different factors, such as environmental exposure and the natural aging process. These factors can lead to abnormalities or mutations in any gene. When genetic mutations accumulate in cells, they can cause the cells to grow abnormally over time. This process leads to tumor formation and malignancy (cancer).

It is estimated that 5 to 10 percent of breast cancers are hereditary, forming from mutations in the BRCA1 and BRCA2 genes. Everyone has BRCA1 and BRCA2 genes. The genes are normally responsible for repairing damage to the cells and suppressing tumor growth in the breasts, ovaries and other cells. When an abnormal copy of either of these genes is passed from generation to generation, it makes the individual carrying the mutation more susceptible to developing breast, ovarian and other cancers.

There are three mutations in the BRCA1 and BRCA2 genes that are seen more frequently in the Ashkenazi Jewish population.  These are called “founder mutations” and associated with developing cancers. Since it is common for Ashkenazi Jews to reproduce with one another, we retain gene mutations within our genetic pool. As a result, these three founder mutations have become more frequent in Ashkenazi Jews and increase susceptibility to breast cancer.

However, having a mutation in the BRCA1 and BRCA2 genes does not mean that you will be diagnosed with one of these cancers. There are many studies that attempt to quantify the risk of developing breast cancer if you have mutations in the BRCA1 and BRCA2 genes. It is also important to understand that genetic studies find participants in different ways. If a study recruits subjects with a family history of breast cancer, it may find that carriers of these mutations develop breast cancer at a higher rate than in a study that identifies carriers from a sample of the general population. In fact, there is ongoing research exploring whether there are more women than we originally expected who have mutations in BRCA1 and BRCA2 but never develop breast cancer. Researchers have even suggested that every Ashkenazi woman, or even every woman regardless of ethnicity, should get tested. The purpose of this is twofold: first, to better understand the mutations from a research perspective and second, so those with these mutations can consider precautions to reduce their susceptibility to cancer, regardless of family history.

It is every woman’s prerogative, whether Ashkenazi or not, to discuss the option of getting tested with her physician. An OBGYN or internist can help point you in the right direction, such as to a genetic counselor, to discuss your personal risk and whether to test for gene mutations, if appropriate. There are certain criteria that are historically utilized to determine if a woman should consider genetic testing for breast cancer gene mutations. These include the number of first and second-degree relatives with breast cancer, personal or family history of breast cancer at a young age, personal or family history of triple negative (estrogen-receptor, progesterone-receptor and Her2neu negative) breast cancer, etc. that can be discussed with medical professionals. If you decide to proceed with testing, there are different panels of genes to consider; you may find that you have a mutation in a gene other than the BRCA1 and BRCA2 founder mutations. This is why it is incredibly important to discuss risk, whether to test and what to test with a physician and/or genetic counselor. If you do not qualify for testing, your physician can suggest precautions based on family history, such as an earlier baseline mammogram to use for comparison later on. Even if you chose to not get genetic testing, it is crucial to discuss screening options (such as mammogram, ultrasound, Breast MRI, etc.) with a physician and when to start based on family history.

There are currently several options to try to reduce the risk of developing cancer in women with a strong family history. These include surgery (removing both breasts and/or ovaries before developing cancer), more frequent and earlier screening, or even medications. While there are several medications commonly recommended to women with a strong family history and others being examined in studies, they are not a “cure” to prevent breast cancer. There is currently ongoing research evaluating other common medications in the hope that something will help reduce the risk of developing breast cancer in BRCA1 and BRCA2 gene mutation carriers or those with a strong family history. Similar to all medications, it is important to weigh the risks and benefits with a physician.

Although the overall goal is to prevent breast cancer in women who have gene mutations that increase cancer susceptibility, there are also exciting advances in treatment research. There are ongoing clinical trials exploring targeted therapy for BRCA1 and BRCA2 gene mutation carriers who develop breast cancer to reduce the risk of the cancer spreading further or developing new breast cancers. The hope is that we will be able to develop treatments to specifically target breast cancers in women with the BRCA1 and BRCA2 gene mutations.

 

Naomi received a MPH in Epidemiology from Mailman School of Public Health, Columbia University. She has been working at the Weill Cornell Breast Center in clinical cancer research since August 2008. She started as a research coordinator for different types of clinical breast cancer treatment trials. Nearly 5 years ago, Naomi transitioned to overseeing the investigator initiated trials and projects, including managing a large clinical trial and a triple negative breast cancer program.