The role of genetics in breast and ovarian cancer

By: Sanford Health News .

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What did you inherit from your parents? Was it eye color, height, body build or hair color? Often, we may hear, “I inherited my eyes from my mother” or “I got my height from my father.” A combination of traits developed from each parent is visible, but the genetics inherited from our parents runs far deeper than physical appearance.

Each of us has a unique genetic code given to us from our parents, and within this code may exist inherited gene changes that increase the likelihood of developing certain conditions, such as some cancers. Though many cancers are sporadic and happen by chance, some have a genetic component related to development. One of these is hereditary breast and ovarian cancer (HBOC), which is commonly linked to one of two gene mutations: BRCA1 and BRCA2.

BRCA are genes that produce tumor suppressor proteins, helping repair damaged DNA and ensuring stability of the cell’s genetic material. HBOC occurs when either BRCA1 or BRCA2 has mutated, causing its protein to either not be produced or function incorrectly, which results in DNA damage not being repaired properly.

“All of us are typically born with two functional BRCA genes, but someone with a mutation has only one functional BRCA gene. Due to this, the patient innately has the inability to repair cell damage, so the person is more likely to develop cancer,” says Maria Bell, M.D., a gynecologic oncologist at Sanford Health.

Each child of a parent who carries a BRCA mutation has a 50 percent chance of inheriting the mutation. And BRCA mutation increases the lifetime risk of developing both ovarian cancer and breast cancer significantly.

Genetic counseling and testing can tell a woman if she has a BRCA mutation. If she tests positive, a provider is able to help her develop a treatment plan that incorporates this gene mutation into care.

Family history is the key indicator for HBOC. Women who have family members diagnosed with breast or ovarian cancer should consider genetic testing for BRCA mutation. Genetic testing can be completed for all children and siblings of anyone known to have a BRCA mutation as well.

Risk of developing HBOC can be reduced in younger women with BRCA mutation by preventing ovulation through using birth control pills.

“In a young woman, I would tell her to go on birth control pills. When she is ready to have children, she can go off birth control pills, and in between children, she should stay on the birth control pill,” says Bell. “Once a woman has finished with childbearing, the recommendation is prophylactic oophorectomy, removing the tubes and ovaries — usually the patient chooses to have her uterus removed at the same time. This has a 95 percent reduction in the development of ovarian cancer.”

Though breast cancer has effective screening tools through mammograms and breast MRIs, the effectiveness of screening tools for ovarian cancer, ultrasound and CA 125 blood test are debated. Genetic testing before developing ovarian cancer is vital. Once the ovaries develop cancer on the surface, it can spread to the abdomen very quickly. Women with HBOC should follow their provider’s screening recommendations.

“Knowledge is powerful. Knowing gives you more control and helps propel action. By knowing, you can do something about it. There are some conditions you can’t do anything about, so genetic testing isn’t relevant, but you can do something about BRCA. You can be proactive and take charge of your health,” Bell says.