Genetics and Breast Cancer: Key Facts Every Woman Should Know
Posted: October 31, 2019 | Word Count: 863
At first, the statistics can sound scary. This year, an estimated 268,600 women in the United States will be diagnosed with breast cancer, making it the second most common cancer diagnosis for women. It is also the second most common cause of cancer death among U.S. women.
However, this Breast Cancer Awareness Month, there is good news to share. Early detection, new generation treatment options and incredible new learnings about the role genes and genetic testing may play in treatment decisions are having a significant impact on survival. Researchers’ knowledge about genetic mutations and their impact on breast cancer development and treatment is helping empower women and their doctors to make more informed healthcare decisions.
Whether you have a family history of breast cancer, have been recently diagnosed, or have received the news that a treated breast cancer has returned, here are five key things to understand about this disease and the role genetics can play:
1. What are the different types of genetic mutations?
There are two major types of gene mutations — inherited and acquired. An inherited (or germline) mutation is present at birth. Like other traits, such as hair or eye color, inherited mutations can be passed on to the next generation by one or both parents. An acquired (or somatic) mutation develops during a person’s lifetime and is present only in a tumor.
2. What genes are important in breast cancer?
Approximately 5-10% of breast cancer cases are hereditary, resulting from gene mutations passed from a parent, and there are a number of different subsequent genetic mutations that are linked to an increased risk. The most common cause of hereditary breast cancer is a mutation in the BRCA1 or BRCA2 gene. BRCA stands for BReast CAncer susceptibility gene. Normally, BRCA genes prevent tumors from growing by repairing damaged DNA. When a BRCA mutation is present, these genes may not work how they are supposed to. As a result, cells may grow and divide to form a tumor.
Another gene associated with breast cancer is the HER2 gene. Approximately 20% of patients diagnosed with advanced breast cancer have a mutation in this gene. When the HER2 gene becomes mutated or defective, too many HER2 receptors develop causing breast cancer to grow and spread more aggressively.
3. What can I do with information gained from genetic testing?
Undiagnosed: People who learn that they have an inherited BRCA mutation can make informed decisions about their future health care, including taking steps to reduce their cancer risk. For example, if you have not been diagnosed with breast cancer, but test positive for an inherited BRCA mutation, your doctor can discuss the option of more aggressive screening methods in addition to an annual mammogram.
Diagnosed: For those who have been diagnosed with localized or metastatic breast cancer (cancer that has spread beyond the breast), testing to determine whether there are any genetic mutations can sometimes alter treatment decisions, as certain types of genetically associated breast cancers are known to be much more responsive to specific treatment courses.
4. Who should consider genetic testing?
Women and men with a previous breast cancer diagnosis who have completed treatment and are considered cancer free should consider BRCA testing. Though it is rarer in men than in women, men can be diagnosed with breast cancer, and having a mutation in the BRCA1 or BRCA2 gene may increase a man’s risk for developing the disease. Men who carry these mutations can also pass them on to their sons and daughters at the same rate that mothers do. Even if a person has tested negative in the past, test sensitivity has increased.
First-degree family members of a person who tests positive for an inherited breast cancer-related gene mutation such as BRCA1 or BRCA2 should also consider testing, as they have a 50% chance of also having that gene mutation. Anyone who has not been diagnosed with breast cancer but is concerned about their risk should speak to their doctor or a genetic counselor about whether genetic testing is right for them.
5. What does genetic testing entail?
A simple blood or saliva test uses DNA to identify inherited mutations such as BRCA gene mutations. For those who have been diagnosed with breast cancer, tumor testing, using a sample of tissue to determine the presence of genetic mutations, can be done as early as diagnosis and is a powerful tool that indicates whether there are mutations in the tumor itself. Both of these forms of testing should be done by a healthcare professional.
During Breast Cancer Awareness Month, take time to talk with your family and medical team about your personal family history and potential risk of breast cancer. If you’re newly diagnosed with breast cancer, it’s important to talk to your doctor about tumor testing and how the results could inform your future treatment decisions.
Knowledge is power. A conversation with your doctor about your genetic make-up as it relates to your risk for developing breast cancer could be the most important conversation you have this year. For more information about breast cancer and genetic testing, visit beBRCAware.com.
This article is sponsored by beBRCAware.