Cancer genes

As a child, Sarah Gabriel’s life was turned upside down when her mother became ill with breast cancer. Sarah’s mother had surgery, chemotherapy and radiation, but she ultimately died of cancer when Sarah was just a teenager. In early adulthood, Sarah’s sister was also diagnosed with breast cancer. It seemed as if history was repeating itself. Sarah and her sister had heard of a gene that causes breast cancer to be inherited in families. Testing for the gene, called BRCA, was available. Should they get the tests and find out if they had inherited the gene? What if they did have BRCA, what would they do about it? Would they just spend their time waiting for cancer to appear? Maybe, it would just be better not to know and to let things take their “natural course.” The questions mounted and the tension grew.
Sarah and her sister ultimately had the tests and the results showed that they both carry a mutation in the BRCA1 gene, an inherited breast cancer gene. Since their mother had breast cancer at an early age, they most likely inherited the gene from her side of the family. Sarah decided to have regular mammograms. The first one was normal, what a relief! But then she found a lump, and it turned out to be a small cancer. Her mind was full of worry. What to do about the cancer? The cancer was small enough that she could have a lumpectomy, but could that be a wise choice given the cancer gene? Should she have both breasts removed to prevent other cancers from developing? Since mutations in BRCA1 can also cause cancer of the ovaries, should they be removed too?
Sarah eventually decided to have bilateral mastectomies, and she had both of her ovaries removed as well. Sarah’s struggles with inherited breast cancer are detailed in her new book, Eating Pomegranates, which will be out in October. It is a frightening story, but it is also a hopeful one.

Part of the hope in Sarah’s story is the terrific advances that are being made in understanding how changes in our genes can cause illness to occur. Doctors are linking changes in our genes to numerous serious diseases, such as diabetes, cancer, and even Alzheimer’s disease. Let’s look at one of these problems, the breast cancer gene that affected Sarah and her family, BRCA.

There are actually two BRCA genes, BRCA1 and BRCA2. They are named after BReast CAncer because they were first discovered in breast cancer patients. BRCA1 and BRCA2 are actually supposed to help prevent cancers. However, in some people changes called mutations occur in these genes. The mutations result in the loss of the cancer prevention activity, so cancer risk goes up. Flaws in the BRCA genes can cause more than just breast cancer. They also increase the risk of cancers of the ovary and prostate gland. If you have a BRCA mutation, you are more likely to get cancer, and the cancers appear at an earlier age. BRCA mutations can make breast or ovarian cancers appear in the 30s or even in the 20s, when we usually think of these cancers as illnesses of women older than 50. Changes in BRCA are passed down from parents to children, so the cancers run in families. BRCA mutations are rare (maybe 5 in 1000 people), but they can cause so much suffering.

If you have multiple relatives who have suffered from breast or ovarian cancer, and especially if someone has had cancers of both breast and ovary, your family may have one of these flawed BRCA genes. There is a blood test that can detect changes in the BRCA gene. If you test positive, you need regular medical tests to prevent cancers from developing. You might need to take the same difficult steps that Sarah did-have surgery to prevent cancers. You don’t need to make these decisions alone. Genetic counseling is available in Willmar or St. Cloud to help you can make an informed decision whether to have genetic tests or not. The state of Minnesota actually has a law in place requiring this counseling before you have genetic tests done.

You might be thinking that maybe you should have some tests to tell you your cancer risk. There are lots of ads out there-just send in a sample of saliva and $300.00 to $1000.00, and they send back a report that tells you if you are “at risk” for cancer. A word of caution: Many of these labs are not very careful. In a recent study from Wall street Journal, the same sample was sent to 3 different labs, and one result said “low risk of leukemia” one said “high risk of leukemia,” and one said “normal risk.” (Hmm…I think there must be a mistake somewhere.) ABC had 5 different volunteers go to different labs to request testing for a prostate cancer gene. There was a discrepancy in 68% of the results. Please talk with your doctor before you spend (waste) your money.