In the general population, 12% of women are likely to develop breast cancer and 1.4% of women will develop ovarian cancer. If a woman has a BRCA mutation, her risk of breast cancer is five times that of a woman without the mutation, or 60%, and the risk of ovarian cancer in a woman with the mutated gene is 15% to 40%. Certain ethnic groups, such as people of Ashkenazi Jewish, Norwegian, Dutch, French Canadian, or Icelandic descent, have a higher predisposition toward cancers caused by a BRCA gene mutation. Patients with a strong family history of certain cancers are also likely to be carriers of BRCA1 or BRCA2 mutations and should be tested. These groups include those with a:
• Personal history of breast cancer before age 50
• Personal history of two primary breast cancers
• Personal history of both breast and ovarian cancer
• Family history of a male breast cancer
• Family history of breast cancer before age 50
• Family history of breast or ovarian cancer in more than one relative
• Family history of both breast and ovarian cancer in one relative
• Known BRCA1 or BRCA2 mutation in the family.
The BRCA gene test is a blood test that uses DNA analysis to identify changes (mutations) in either one of two breast cancer susceptibility genes — known as BRCA1 or BRCA2. Genetic counseling also is part of the BRCA gene test process. After having a BRCA gene test performed, you learn whether you carry an inherited BRCA gene mutation and receive an estimate of your personal risk of breast cancer and ovarian cancer. Since the BRCA gene test is a blood test, a doctor, nurse or medical technician inserts a needle into a vein, usually in your arm, to draw the blood sample needed for testing. Your blood sample then goes to a laboratory for DNA analysis. It takes about three to four weeks before test results are available. In most cases, you meet with your genetic counselor again to learn your test results, discuss their implications and go over your options.
So far, researchers have found two genes linked with breast cancer—labeled BRCA1 and BRCA2—that everyone inherits in pairs: one from our mother and one from our father. When they function normally, they are supposed to stop the growth of cancerous cells in the breast. When both genes in a pair are damaged, they don’t work properly and cancer may develop. People who inherit a damaged BRCA1 or BRCA2 gene from one parent are at greater risk of developing breast cancer than people who inherit two normal genes. The fact I was diagnosed before age 50 and now that my mother has been diagnosed along with knowing that I have had a few relatives on my mother's side die from cancer (one was melanoma, the other I'm unsure about) and having had a cousin with either cervical or ovarian cancer, I guess I better find out!