BRCA1 and BRCA2 are genes that every person has. Their job is to produce proteins that repair damaged DNA inside your cells, acting as a built-in defense against cancer. When either gene carries a harmful mutation, that repair system doesn’t work properly, and the risk of developing certain cancers, particularly breast and ovarian cancer, rises significantly.
The names stand for BReast CAncer gene 1 and BReast CAncer gene 2. Despite the name, these genes affect more than just breast tissue, and they matter for men as well as women.
How BRCA Genes Protect Against Cancer
Your DNA takes damage constantly, from normal cell division, sun exposure, environmental toxins, and simple metabolic processes. Most of the time, your body fixes this damage before it causes problems. BRCA1 and BRCA2 proteins are key players in one of the most precise repair methods your cells have: a process that uses the undamaged copy of a DNA strand as a template to fix the broken one.
You carry two copies of each gene, one inherited from each parent. Having just one normal copy of either gene is enough to keep the repair system running. Problems arise when both copies are compromised. In someone born with a BRCA mutation, every cell already has one faulty copy. If the second copy gets damaged through the normal wear and tear of life, that cell loses its DNA repair ability entirely. Damaged DNA accumulates, and the cell can become cancerous.
This is why a BRCA mutation doesn’t guarantee cancer but dramatically increases the odds. It removes one layer of protection that healthy cells rely on.
Cancer Risks for Women
The cancers most strongly linked to BRCA mutations are breast cancer and ovarian cancer. In the general population, roughly 13% of women develop breast cancer during their lifetime. For women with a harmful BRCA1 or BRCA2 mutation, that risk climbs to somewhere between 45% and 72%, depending on the specific mutation and other individual factors.
Ovarian cancer risk tells a similar story. The average woman faces about a 1.2% lifetime risk. With a BRCA1 mutation, that figure rises to around 39 to 44%. BRCA2 mutations carry a somewhat lower but still substantial ovarian cancer risk of roughly 11 to 17%.
BRCA1 mutations tend to be associated with cancers that develop at younger ages and with a more aggressive subtype called triple-negative breast cancer, which doesn’t respond to hormonal therapies. BRCA2 mutations are more commonly linked to hormone-receptor-positive breast cancers, which generally have more treatment options. Both mutations can lead to cancer in either breast and increase the chance of developing a second, independent breast cancer after the first.
Risks Beyond Breast and Ovarian Cancer
BRCA mutations raise the risk of several other cancers that get less public attention. Men with BRCA2 mutations have an elevated risk of prostate cancer, and that cancer tends to be more aggressive than average. Male breast cancer, while rare overall, is also more common in BRCA2 carriers. Pancreatic cancer risk increases with mutations in either gene, though the absolute numbers remain relatively small.
BRCA2 mutations have also been linked to higher rates of melanoma. Because these genes are fundamentally about DNA repair, their dysfunction can show up wherever cells divide rapidly or face DNA-damaging exposures.
How BRCA Mutations Are Inherited
BRCA mutations follow an autosomal dominant inheritance pattern, which means a few important things. First, the mutation sits on a non-sex chromosome, so men and women carry and pass it on equally. Second, you only need to inherit one mutated copy (from either parent) to be a carrier. If one of your parents has a BRCA mutation, you have a 50% chance of inheriting it.
This is why family history matters on both sides. A father who carries a BRCA2 mutation may never develop cancer himself but can pass the mutation to a daughter who faces significantly elevated breast and ovarian cancer risk. Many people discover their BRCA status only after a cancer diagnosis in themselves or a close relative prompts genetic testing.
Certain populations carry BRCA mutations at higher rates. Among Ashkenazi Jewish individuals, three specific founder mutations in BRCA1 and BRCA2 are common enough that broader genetic screening is often recommended regardless of family history. In one study of over 5,000 Jewish participants, 10% of Jewish women diagnosed with breast cancer in their forties carried one of these mutations.
Genetic Testing and What Results Mean
BRCA testing is done through a blood or saliva sample. Results typically fall into three categories. A positive result means a known harmful mutation was found. A negative result means no mutation was detected, though this is most meaningful when a specific family mutation has already been identified. If no one in your family has been tested, a negative result doesn’t completely rule out hereditary risk from other genes.
The third possibility is a variant of uncertain significance, or VUS. This means a change in the gene was found, but scientists don’t yet have enough data to know whether it’s harmful or harmless. A VUS is not treated as a positive result. Over time, as more data accumulates, many variants get reclassified, so your result could be updated years later.
Testing is typically recommended for people with a strong family history of breast, ovarian, or pancreatic cancer, those diagnosed with breast cancer at a young age, people with triple-negative breast cancer, men with breast cancer, and individuals of Ashkenazi Jewish descent. A genetic counselor can help interpret results and put the numbers into context for your specific situation.
Screening for BRCA Carriers
Because BRCA-related cancers can develop earlier than typical cancers, screening starts sooner and involves more tools. The American College of Radiology recommends that women with BRCA mutations begin annual breast MRI screening between ages 25 and 30. Mammography can be delayed until age 40 as long as annual MRI is being done. This dual approach catches cancers that mammography alone would miss, especially in younger women whose breast tissue is denser.
Ovarian cancer screening is more challenging because no reliable early-detection method exists for the general population. Some carriers undergo regular transvaginal ultrasounds and blood tests, but these tools have significant limitations and don’t catch ovarian cancer as effectively as breast screening catches breast cancer.
Reducing Cancer Risk
For BRCA carriers, risk-reducing surgery is the most effective prevention strategy available. Preventive mastectomy, the removal of breast tissue before cancer develops, reduces breast cancer risk by over 90%. Some women choose this option in their thirties or forties after completing breastfeeding, while others opt for intensive screening instead.
Preventive removal of the ovaries and fallopian tubes (salpingo-oophorectomy) reduces ovarian cancer risk by over 90% as well. A small residual risk of peritoneal cancer remains, estimated at 1 to 3%, which is comparable to the average person’s baseline ovarian cancer risk. This surgery is generally recommended between ages 35 and 40 for BRCA1 carriers and by age 45 for BRCA2 carriers, since BRCA1-related ovarian cancers tend to develop earlier. Removing the ovaries before menopause also provides some reduction in breast cancer risk because it lowers estrogen levels.
For those who prefer nonsurgical approaches, certain hormonal medications can reduce breast cancer risk, though by a smaller margin than surgery. The decision between surgery and surveillance is deeply personal, influenced by the specific mutation, family history, age, and individual priorities.
How BRCA Status Affects Treatment
If cancer does develop in someone with a BRCA mutation, knowing their genetic status actually opens up specific treatment options. Because BRCA-mutated cancer cells can’t repair their DNA effectively, they’re especially vulnerable to treatments that cause DNA damage. Platinum-based chemotherapy drugs exploit this weakness directly.
A class of targeted drugs called PARP inhibitors takes a different approach. These drugs block a backup DNA repair pathway that cancer cells rely on when BRCA repair is already broken. With both repair systems disabled, the cancer cells accumulate so much DNA damage that they die. PARP inhibitors have become a standard part of treatment for BRCA-related ovarian and breast cancers and are now being studied in other cancer types as well.
This is one of the clearer examples in oncology where knowing your genetic makeup directly changes which treatments work best. For people already diagnosed with cancer, BRCA testing can shape the treatment plan in ways that improve outcomes.