BEYOND BRCA: HEREDITARY BREAST CANCER GENETIC TESTING

By Athena Puski, MS LGC Licensed Genetic Counselor Holden Comprehensive Cancer Center University of Iowa Hospitals and Clinics

You’ve probably heard of BRCA1 and BRCA2, or “the BRACA genes,” which increase the risk of getting breast and ovarian cancer. But have you heard of PALB2, CHEK2, or ATM? Many are surprised to learn there are 11 additional genes besides BRCA1 and BRCA2 that are known to increase the risk of getting breast cancer, and many more genes are still being researched for their possible association with hereditary breast cancer. A mutation in any of these “other” genes increases the chance of getting breast cancer. Some increase the risk for breast cancer just a little bit, while others increase the risk a lot. These genes can also increase the chance of getting other cancers besides just breast cancer. For example, CHEK2 mutations slightly increase the risk for breast cancer and colon cancer, while PALB2 mutations slightly increase the risk for pancreatic cancer, ovarian cancer, and breast cancer. Knowing if you have one of these genetic mutations can impact medical care for you and your family members. There are often steps that can be taken to detect cancer at an early and more-treatable stage, or even prevent cancer. How this is done depends on the specific gene in which there is a mutation. It may include screening for cancer more often, such as doing a mammogram and a breast MRI every year. Sometimes surgery can be used to prevent cancer, such as by removing the ovaries or both breasts. Medications can also sometimes be used to lower the chance of getting cancer. In some cases, targeted cancer treatments, such as PARP inhibitors, can be used as part of the treatment for breast cancer. These hereditary causes of cancer are not common—only about 10% of all breast cancers are estimated to be due to an inherited genetic mutation (about half of which are due to a mutation in a gene other than BRCA1 or BRCA2). Those with a genetic mutation often (but not always) have a strong family history of cancer. Some things that can indicate you might have a hereditary breast cancer condition and may want to consider genetic testing include the following: • You or someone in your family had breast cancer before the age of 45 • You or someone in your family has had triplenegative breast cancer, ovarian cancer, pancreatic cancer, male breast cancer, or metastatic prostate cancer • At least three members of your family have had breast cancer or prostate cancer at any age If genetic testing is something you are interested in learning more about, talk with your doctor or a genetic counselor. Even if you had BRCA1 and BRCA2 genetic testing in the past, additional testing for mutations in other genes may be appropriate. This type of genetic testing is called “update testing” or “panel testing.” Genetic testing can usually be done with a blood sample or sometimes a saliva sample. Nowadays, insurance coverage for genetic testing is often very good. However, even if insurance won’t cover the cost of testing for you, there are routes available to get genetic testing for about $250, even without insurance. Genetic testing isn’t right for everyone, though, and that’s okay. It is scary to learn you and family members have an increased chance of getting cancer; not everyone is ready for this information. Others may welcome the information learned from genetic testing so they can take proactive steps against their cancer risk. A genetic counselor and your doctor can help you determine what is best for you. FORCE (https://www.facingourrisk.org/) is also great resource to learn more about genetic testing and genetic mutations. Whether or not you decide if genetic testing is right for you, knowing your family history is key. The upcoming holidays are a great time to talk with family members and gather their medical history. Here is a guide to help you through the process about asking family members about their health history: guide-tofamily-health-history.pdf (geisinger.org).