There are two BRCA (Breast Cancer) genes–BRCA 1 and BRCA 2. Both are tumor suppressor genes which produce a protein that helps prevent cells from multiplying and dividing too rapidly. They are also involved with repairing damaged DNA in cells. When a mutation in these genes occur, they can work improperly. As a result, there is an increased risk of cancer.
Each person has two copies of these genes, one from each parent. If there is a mutation in one or both of these genes, it can increase your risk of breast, ovarian, and other specific cancers. According to the National Cancer Institute (NCI), mutations of BRCA 1 and BRCA 2 account for 20–25% of all hereditary breast cancers, about 5–10% of all breast cancers, and around 15% of all cases of ovarian cancer. The NCI further states that 12% of the general population of women will develop breast cancer, but 55–65% of women with a mutated BRCA 1 gene and 45% with a mutated BRCA 2 gene will develop it. Furthermore, the NCI states that 1.4% of women will develop ovarian cancer, but 39% with a mutated BRCA 1 and 11–17% with a mutated BRCA 2 gene will develop it. In addition, there may be increased risks of both Fallopian tube and peritoneal cancer when there is a mutated BRCA 1 gene. Mutations of the BRCA 1 and/or BRCA 2 genes may also increase your risk of other cancers. These can include colon, skin, pancreas, gallbladder, bile duct, and stomach cancers.
Facing Our Risk of Cancer Empowered (FORCE) reminds women that different studies of families with BRCA mutations have found different lifetime risks for cancer. For instance, one study of mutations common in the Jewish population found a lifetime cancer risk of about 85%. Thus, it is important to work with a specialist in cancer genetics to determine your personal cancer risks and how you can make decisions to minimize those risks. FORCE further indicates that new research continues, so you should always stay in contact with a genetic expert to stay up-to-date on the latest information.
A mutation of BRCA 1 and/or BRCA 2 does not automatically mean you will develop cancer; it only means you have an increased risk. According to the American Cancer Society, genetics is only one possible cause for cancer. Other factors include lifestyle (tobacco use, diet, physical activity), certain types of infections, and environmental issues. Your cancer risk may involve a combination of the factors, your reproductive history, and genetics factors besides BRCA 1 or BRCA 2 mutations. In addition, women without BRCA 1 or BRCA 2 mutations can still develop both breast and ovarian cancer.
Mutated BRCA 1 or BRCA 2 are rare, so without a family history of cancer genetic testing is not necessary. However, if you have a family member who is BRCA 1 or BRCA 2 positive, then you should consider genetic counseling to determine if genetic testing is right for you. If there are multiple cases of breast and/or ovarian cancer in your family, two or more primary cancers in a single family member, and/or cases of male breast cancer in your family, then you should consider seeing a genetic counselor to see if genetic testing would be beneficial for you.
This content was written by staff of HysterSisters.com by non-medical professionals based on discussions, resources and input from other patients for the purpose of patient-to-patient support. Reprinted with permission: BRCA Information