Genetic Testing
All in the Family
Joyce Parmentier watched her own mother struggle with breast cancer twice—once when she was 49 years old and again when she was 63. Joyce’s aunt was diagnosed with breast cancer at an early age and several cousins have been diagnosed as well. “When I sat down with my mom and did the family history, my mother’s side was loaded with breast cancer,” recalls the 65-year-old resident of Blackstone. “It was awful.”
Joyce feared that it was only a matter of time until she also faced cancer. At the age of 46, her fear came true. Joyce was diagnosed with breast cancer. After a subsequent mastectomy, Joyce is happy to say she is doing well today. Dr. Mona Kaddis, Joyce’s medical oncologist at Dana-Farber/Brigham and Women’s Cancer Center at Milford Regional (DFBWCC), told her that her cancer could be caused by a genetic mutation that had been unknowingly passed down through her family. If they could pinpoint the specific mutation through genetic testing, they might be able to take proactive steps to get other family members tested and begin preventive treatment before cancer has the chance to develop. She referred Joyce to a genetic counselor for further evaluation.
According to Dr. Huma Rana, a Dana-Farber Cancer Institute geneticist who now sees patients monthly at DFBWCC at Milford Regional, testing of the BRCA1 and BRCA2 genes (among others) can help to explain why some families develop breast or ovarian cancers. These genes, which produce important proteins that repair naturally-occurring damage to DNA, are crucial to the body’s healthy functioning. All individuals are born with two copies of BRCA1 and BRCA2. However, some individuals are born with one non-working mutated copy of one of these genes. If the second copy mutates and stops working spontaneously, production of the protein ceases, and DNA damage cannot be repaired.
“When this happens, cell growth becomes unregulated,” explains Dr. Rana. “There are no checks and balances to ensure that errors are appropriately fixed. Errors accumulate on top of errors within the DNA of the cells and, as you can imagine, this process leads to unyielding growth and eventually tumor growth and cancer.”
Those with a BRCA mutation are at greater risk of developing breast and ovarian cancer, says Dr. Rana. The good news is that only one in 400 people carry a BRCA mutation; however, possessing the BRCA mutation puts individuals at significantly higher risk of developing cancer as compared with the general population. While one in eight women in the general population will develop breast cancer, women with a BRCA mutation have a 50%-85% chance. For men, fewer than one in 1,000 men in the general population will develop breast cancer. Those with a BRCA2 mutation have a higher risk of developing breast cancer as well as more aggressive forms of prostate cancer. The more removed a person is from the individual with the BRCA mutation, the lower the cancer risk, states Dr. Rana. Children of an individual with a BRCA mutation have a 50/50 chance of inheriting the mutation. Aunts and uncles have a 25% chance of possessing the mutation, and cousins have a 12.5% chance. “It’s always recommended that the person in the family who has the cancer be the first to be tested,” says Dr. Rana. “Their testing is the most informative for the entire family as well as themselves.”
Joyce knew that undergoing the genetic test for the BRCA mutation would identify the cause of her cancer and provide her children—two sons and a daughter—with important information that they could use to manage their own health. During the initial hour-long appointment with the genetic counselor, Joyce provided a detailed three-generation family history of cancer that she collected based on paperwork she received and completed before her appointment. “The paperwork prompts a lot of patients to start calling family members to ask questions and gather information,” says Claire L. Healy, a certified genetic counselor who works alongside Dr. Rana and meets with patients twice a month at DFBWCC.
When Joyce’s test—a simple blood test—revealed that she had a BRCA2 mutation, she immediately encouraged all three of her children to get tested as well. Joyce’s daughter, Patty, a 42-year-old resident of Blackstone and mother of three, underwent the test and discovered she had a BRCA2 mutation. Although she has no personal history of cancer, she decided to proactively have her ovaries removed, knowing that she was at a much higher risk of developing ovarian cancer. She is also taking Tamoxifen to decrease her risk of developing breast cancer. “I’m glad that I had the test,” she says resolutely. “I wanted to know what I might be passing down to my children, and I wanted to be watched more closely than the average patient. I’m living a normal life because I can be proactive.”
Joyce’s son, Dan, who also underwent the test, discovered he had the BRCA 2 mutation as well. “I wanted to know if I had it so I’d know whether I was more susceptible for certain types of cancer,” he says. And like his sister Patty, this 37-year-old resident of Bellingham is concerned about passing the mutation down to the next generation. Joyce’s third child, a son, tested negative for the mutation, taking him out of the high risk category.
Those who test positive for the mutation generally have two options, explains Dr. Rana: surveillance (including a breast exam every six months and a breast MRI and mammogram annually starting at age 25), or risk reduction (including a bilateral mastectomy, chemo-prevention, or salpingo-oophorectomy [removal of the ovaries and fallopian tubes]). Joyce and her family are one of a growing number of patients seeking genetic counseling to make more informed healthcare decisions. Dr. Rana says that recent increased press coverage has raised awareness. In addition, the Supreme Court recently held that genomic sequences may not be patented, allowing various laboratories to complete genetic testing at lower costs. “The ultimate goal of genetic testing for BRCA is to empower high-risk families and individuals to make decisions that are best for them,” says Dr. Rana.
Joyce is so thankful that she had the test and believes that vigilance is key. She undergoes a mammogram and MRI annually and also takes a low-dose pill of chemoprevention. “If I can do anything that helps my grandchildren learn something about themselves, that’s what’s important,” emphasizes Joyce. “We need to know for them so they can prolong their lives.”
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