Empowering Breast Cancer Patients with Genetic Testing
In 2013, Academy Award-winning actress Angelina Jolie wrote a now famous opinion piece for the New York Times detailing her journey involving genetic testing for breast and ovarian cancer. The filmmaker and humanitarian, whose mother and aunt died of ovarian and breast cancer, respectively, was determined not to fall victim to the same fate.
Jolie worked with her doctor to undergo genetic testing for several different genes that, when they mutate, increase a woman’s risk of developing breast cancer and ovarian cancer.
The two most commonly mutated genes associated with breast cancer are BRCA1 and BRCA2. BRCA stands for BReast CAncer susceptibility gene. First discovered in 1990, BRCA1, like its cousin BRCA2, codes for a protein that helps repair damaged DNA inside the cell. When someone inherits a faulty copy of BRCA1 or BRCA2, their body cannot repair damaged DNA as efficiently, and this eventually can lead to certain forms of cancer.
A woman with a disease-causing mutation in BRCA1 or BRCA2 has a 69 – 72 percent chance of developing breast cancer by age 80. In contrast, the average risk of breast cancer in the same timespan for someone without a BRCA1 or BRCA2 mutation is about 12 percent. Similarly, the risk of developing ovarian cancer by age 80 is 44 percent in a woman with a BRCA1 mutation and only 17 percent in a woman with a BRCA2 mutation, compared to a risk of about 1.3 percent in women without mutations in either gene. Furthermore, the risk of pancreatic cancer increases from about 0.5 percent to 1 – 7 percent for both men and women with a BRCA1 or BRCA2 mutation.
Mutations in the BRCA1 and BRCA2 genes not only increase the risk of developing cancer, the cancer also tends to strike people at a younger age. In addition, men with a mutation in BRCA1 or BRCA2 are at increased risk of developing breast cancer and prostate cancer.
After learning she had inherited a mutation in her BRCA1 gene, Jolie decided to undergo preventive surgery to remove the tissue from both breasts – called a mastectomy. Although a mastectomy does not completely eliminate the possibility of breast cancer, it can drastically reduce the risk that women with a BRCA1 or BRCA2 mutation will develop the disease. Removing the ovaries after a woman is done having children is another option for women with a BRCA1 or BRCA2 mutation to reduce overall cancer risk.
Diagnostic genetic testing, which can tell more about whether you have a mutation in your BRCA1 or BRCA2 genes, is becoming more accessible as the technology to sequence DNA continues to improve and become less expensive. Talking with a primary care doctor or gynecologist, combined with guidance from a genetic counselor to discuss your family history of cancer, can help determine if genetic testing is the right decision for you.
The University of Arizona Center for Applied Genetics and Genomic Medicine (TCAG2M) is helping increase awareness about the benefits of genetic testing for precision medicine. TCAG2M partnered with the Department of Cellular and Molecular Medicine to develop the UA Genetic Counseling Graduate Program, which is training the next generation of genetic counselors to work with patients on complex genetic testing options throughout the state. In addition, TCAG2M sponsors community engagement events focused on genetic testing. A yearly presentation called Genes on Screen increases awareness about advances in genetic testing. To learn more about TCAG2M, visit http://precisionhealth.uahs.arizona.edu.