Misconceptions re Gene Mutations
Genetic testing has been especially on my mind over the past few weeks. Because my mother had post-menopausal breast cancer and because my first breast cancer was diagnosed when I was in my early 40s, I had the genetic testing a number of years ago. The results were negative. When my second breast cancer was diagnosed in 2005, I thought again about this and lamented how little we know about the causes of cancer.
Earlier this summer, my older daughter had an appointment with a high risk breast clinic in the city where she lives. She needed copies of some of my records and whatever information I had about my mother and other family members. This stimulated me to speak again with my doctor who said that the genetic mutation test had been improved since my first test, and there was another rare (about 8% of the total positives) variant that could now be identified. She speculated that the chances of my having that variant were less than 1%, but it still seemed worth doing as my daughters are, of course, vigilant and concerned about their own health. All this is to say that I had the blood test again and, again, blessedly, the results were negative. This is excellent news for my daughters, but still leaves me with all the unanswered questions about "why".
Enough background. This is a good short article from Living Beyond Breast Cancer (www.lbbc.org) about common misconceptions re genetic mutations and testing.
Five Common Misconceptions About
Genetics and Breast Cancer
By Debbie Lerman, for LBBC
1. MISCONCEPTION: Most breast cancers are inherited.
Actually, only about 5 percent to 10 percent of all breast cancers are thought to be caused by an inherited genetic mutation. This means that 90 percent to 95 percent of breast cancers are caused by other risk factors during a person's lifetime.
2. MISCONCEPTION: You can only inherit breast cancer gene mutations from your mother's side of the family.
You have an equal chance of inheriting a mutated BRCA1 or BRCA2 gene from your father's side of the family. A genetic counselor can explain how the genes are passed from generation to generation.
3. MISCONCEPTION: Getting a positive result on a genetic test will give you a clear prevention or treatment plan.
There are many options for preventive steps if you test positive for an inherited breast cancer gene mutation. Decisions about prevention are very personal and cannot be determined just based on your test results. Consider talking with your doctors and genetic counselors, getting second and even third opinions if you feel they might help and discussing options with your family before deciding. Support groups for women at high risk for developing breast cancer and online resources can also help.
4. MISCONCEPTION: Getting a negative result on a genetic test will give you a clear prevention or treatment plan.
As with a positive test result, negative results do not provide a final answer on whether you should take certain preventive steps. For example, if you test negative for BRCA mutations, but you have a strong family history of breast or related cancers, you might still consider prophylactic (preventive) surgery or other treatments to reduce your risk. Consider all your options and discuss them with your genetic counselor, your healthcare team, family and other women who have had similar experiences.
5. MISCONCEPTION: Testing positive for BRCA1 or BRCA2 is basically the same thing.
Actually, researchers have found some important differences between the two breast cancer genes. One of the main differences is that BRCA2 is associated with other malignancies such as melanoma, pancreatic cancer and stomach cancer in addition to breast and ovarian cancer; BRCA1 is not.
BRCA Mutation Risk Factors
By Debbie Lerman, for LBBC
Genetic testing is not recommended for most people with breast cancer. Instead, genetic testing is useful if you and your family have a health history that points to a cancer-related genetic mutation being passed from one generation to another. Your genetic counselor may ask questions to find out whether your family fulfills one or more of the following criteria:
• A premenopausal breast cancer diagnosis in the family
• A diagnosis before age 50 with a triple-negative breast cancer, meaning the cancer is estrogen receptor-negative (ER-), progesterone receptor-negative (PR-) and HER2 negative
• Multiple family members affected by breast cancer on the same side of the family
• Ovarian cancer in the family
• Pancreatic cancer in the family at a young age, in combination with family history of breast cancer
• The family is of Ashkenazi (Eastern European) Jewish descent. About 2.5 percent of Ashkenazi Jews have the genetic mutations with the strongest known link to breast cancer, which is ten to 20 times higher than the general population
• A member of the family has had both breast and ovarian cancer or multiple breast cancers
• Male breast cancer in the family
• Medullary breast cancer in the family, where the border between the cancer tissue and the normal tissues is relatively well-defined (associated with the breast cancer gene BRCA1)