Decoding Genetic Predisposition: Understanding BRCA Gene Mutations
Decoding Genetic Predisposition: Understanding BRCA Gene Mutations
Unraveling BRCA Gene Mutations and Breast Cancer Risk
BRCA gene mutations, specifically the BRCA1 and BRCA2 genes, are associated with a genetic predisposition to breast cancer. These genes normally play a crucial role in repairing damaged DNA. When mutations occur, their ability to repair DNA damage becomes compromised, which can lead to the unchecked growth of abnormal cells, ultimately increasing the likelihood of cancer development.
An estimated 45% to 72% of women who carry these harmful gene mutations will develop breast cancer in their lives, compared to about 13% of the general population. Although breast cancer in men is rare, men who carry the genes have an increased risk of 1% to 10%. Hereditary breast cancer typically presents earlier in life and is likely to develop contralaterally within 20 years if it develops in one breast first.
Several factors may influence the risk, including which mutation is inherited. BRCA1 presents a slightly higher risk of developing breast cancer compared to BRCA2, but both are uncommon, comprising only 5% to 10% of all breast cancer diagnoses. Carrying either mutation is not an absolute indicator that you will develop the disease.
Inheritance Patterns and Genetic Impact
Either parent can pass down a harmful BRCA1 or BRCA2 variant, so a child with one parent who carries either mutation has a 50% chance of inheriting it, which is linked to an increased risk of developing cancer. Even if the other copy of the gene is normal, the presence of one mutated BRCA gene can outweigh the protective effects of the normal copy. When one gene mutation is sufficient to cause a particular health condition, this is called autosomal dominant inheritance.
Inheriting two BRCA mutations is extremely uncommon and most embryos with two harmful variants will not develop to full-term. In the rare instances that a child with two BRCA mutations is born, they will develop Fanconi Anemia, a disorder that affects the bone marrow, leading to too few blood cells and other severe health conditions.
Identifying BRCA Mutations through Genetic Testing
Genetic testing for BRCA mutations can be performed on individuals who are suspected to have inherited a harmful variant due to a family history of breast cancer. When possible, the cancer patient or survivor should be tested first to get a clear indication of whether the cancer is hereditary, but undiagnosed family members may also be tested to determine whether they’re a carrier. Knowing whether or not you’ve inherited a harmful BRCA variant empowers you to make informed decisions about your health to either reduce the risk of cancer or avoid unnecessary tests and procedures.
BRCA testing can be conducted through a straightforward blood or saliva sample, with results typically available within two weeks. Our genetic counselors prefer to discuss the results in person to discuss the implications and next steps and answer your questions. Many patients find relief in having answers after getting tested, regardless of whether the result is positive or negative.
A positive test result for BRCA1 or BRCA2 mutations indicates a genetic predisposition for breast cancer and other conditions. It’s not a diagnosis. However, it does emphasize the need for early detection and proactive screening. You may also consider risk-reducing strategies like oral contraceptives, prophylactic surgeries, chemoprevention, or other targeted therapies. A negative test indicates that you should follow the same best practices as the general population to monitor for breast abnormalities. When you receive your results, our team will be a source of knowledge and support so that you can better understand your genetics and make informed decisions about your care plan.
Beyond Breast Cancer: BRCA Mutations and Other Cancers
Those who’ve inherited a harmful BRCA variant must be aware that they’re also at an increased risk of developing several other types of cancer. An estimated 11% to 44% of women with a BRCA mutation will develop ovarian cancer in their lifetime, compared to about 1.2% of the general population. Men face an increased risk of prostate cancer and both men and women have an increased risk of pancreatic cancer. Different types of cancers may present earlier in BRCA1 or BRCA2 carriers, demonstrating the importance of ongoing screening, preventative care, and comprehensive health management.
Informed Decision-Making and Preventive Measure
Genetic counseling allows you and your healthcare provider to assess your breast cancer risk factors, as well as your risk for other cancers, then create an individualized care plan to be proactive, give you peace of mind, and equip you with the tools to continue living your life to the fullest.
Potential treatment options for mitigating your cancer risk include:
- Enhanced breast cancer screening – Women can begin screening for breast cancer more frequently, at a younger age, and with an MRI in addition to a mammogram.
- Prostate-specific antigen (PSA) testing – Men may consider PSA testing for prostate cancer screening starting at age 40.
- Screening for other types of cancer – Some experts recommend those with a hereditary disposition for pancreatic and other cancers screen regularly with an ultrasound or MRI.
- Oral contraceptives – Both women in the general population and those with detrimental BRCA1 or BRCA2 mutations who use oral contraceptives exhibit roughly a 50% reduced risk of ovarian cancer.
- Prophylactic surgeries – Risk-reducing surgery for women involves bilateral mastectomy (removal of both breasts) or bilateral salpingo-oophorectomy (removal of the ovaries and fallopian tubes). The goal is to remove as much of the at-risk tissue as possible and eliminate a source of hormones that may fuel breast cancer. A study of women who underwent the latter procedure experienced up to an 80% reduced risk of dying from cancers caused by a harmful BRCA mutation.
- Chemoprevention – Some research suggests that chemopreventive drugs, including tamoxifen and raloxifene, may reduce the risk of cancer in people who have a higher-than-average likelihood of developing it. The most common kind of breast cancer found in men is one of the same kinds that occurs in women:
Our team of breast surgeons in New Jersey will work with you to understand the potential benefits and drawbacks of each risk-reducing treatment. Each approach comes with additional risk factors that different individuals may be more sensitive to, including radiation, false-positive findings, complications from surgery, infection, early menopause, undesirable side effects, and psychological factors such as anxiety and poor body image. Everyone comes from a different health background and must be given the opportunity to decide which treatment option will best suit their lifestyle while addressing their medical needs.