Angelina Jolie’s announcement that she is a carrier of the BRCA1 mutation and her subsequent decision to have a preventive double mastectomy has prompted a lot of discussion.
One question Jolie doesn’t touch on: the Supreme Court is currently determining if human genes can be patented. Myriad owns or licenses two human genes linked to breast and ovarian cancer. If you need BRCA1 or BRCA2 testing, as Jolie did, Mryiad has your fate in their hands. The Supreme Court ruling is expected in June 2013. We’ll look at that issue in a separate post.
In the interim, here are some basic facts about breast and ovarian cancer:
- Most cancer just happens–it’s sporadic vs. hereditary. The majority of people who develop breast cancer didn’t inherit an abnormal breast cancer gene and have no family history. But about five percent of people have a genetic mutation which predisposes them to cancer.
- Two abnormal genes BRCA1 (BReast CAncer gene one) and BRCA2 (BReast CAncer gene two) are associated with a higher lifetime risk of developing breast and/or ovarian cancer. (FYI, I do NOT have this mutation, my cancer is considered sporadic; I may well have some mutation for which there’s currently no test.)
- From the NCI FAQ: A woman who inherits a harmful mutation in BRCA1 or BRCA2 has an increased risk of developing breast and/or ovarian cancer at an early age (before menopause) and often has multiple, close family members who have been diagnosed with these diseases. Harmful BRCA1 mutations may also increase a woman’s risk of developing cervical, uterine,pancreatic, and colon cancer (1, 2). Harmful BRCA2 mutations may additionally increase the risk of pancreatic cancer, stomach cancer, gallbladder and bile duct cancer, and melanoma(3).
- All of us have BRCA1 and BRCA2 genes according to BreastCancer.org: ” The function of the BRCA genes is to repair cell damage and keep breast cells growing normally. But when these genes contain abnormalities or mutations that are passed from generation to generation, the genes don’t function normally and breast cancer risk increases. Abnormal BRCA1 and BRCA2 genes may account for up to 10% of all breast cancers, or 1 out of every 10 cases.”
- Ashkenazi (Eastern European) Jews are 10 times more likely to have mutations in BRCA1 and BRCA 2 genes than the general population. Approximately 2.65 percent of the Ashkenazi Jewish population has a mutation in these genes, while only 0.2 percent of the general population carries these mutations.
- Note that most U.S. Jews are Ashkenazi (their ancestors came from Eastern Europe) vs. Sephardic (their ancestors came from Spain, Portugal, North Africa and the Middle East).
- Having an abnormal BRCA1 or BRCA2 gene doesn’t mean you will be diagnosed with breast cancer: Only seven percent of breast cancers in Ashkenazi women are caused by alterations in BRCA1 and BRCA2 (See www.genome.gov/10000507.)
Perils of ill-informed celebrity spokespeople (kudos to Jolie):
“Sweet Valley High” ghostwriter explores her family’s history of ovarian and breast cancer:
My experience with BRCA1 and BRCA2 testing:
Great info. I’d just add two small bits–
– new mutations of BRCA are being found. Myriad should offer retesting for these. However, even their basic testing doesn’t test for all known mutations.
– It is important to remember that the gene mutation CAN be passed down by fathers. Someone whose faulty gene came from their father’s father’s father isn’t likely to have many relatives to have been affected (other than aunts).
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