A BRCA mutation is an inherited change in one of two genes, BRCA1 or BRCA2, that normally protect you from cancer by repairing damaged DNA. When either gene carries a harmful mutation, that repair system breaks down, and the lifetime risk of breast cancer rises to over 60%. The mutation also increases the risk of ovarian, prostate, pancreatic, and other cancers.
Everyone has two copies of both BRCA1 and BRCA2. These genes aren’t inherently dangerous. They’re actually essential. Problems arise only when a copy is altered in a way that prevents the protein it makes from doing its job.
What BRCA Genes Normally Do
Your DNA breaks constantly. Ultraviolet light, normal cell division, even routine metabolic processes create damage, including the most dangerous type: double-strand breaks, where both rails of the DNA ladder snap at roughly the same spot. Left unrepaired, these breaks can scramble chromosomes, delete critical instructions, or trigger uncontrolled cell growth.
BRCA1 and BRCA2 proteins are central to the most precise repair method your cells have. This system uses an undamaged copy of the same DNA sequence (from the matching chromosome) as a template, essentially reading the backup copy to restore the broken one perfectly. BRCA1 acts as a coordinator, directing the cell to choose this high-fidelity repair pathway over faster but sloppier alternatives. BRCA2 handles a more specific task: it physically loads a repair protein called RAD51 onto the broken strand so it can find and read the matching template. BRCA2 also stabilizes stalled DNA copying machinery during cell division, preventing additional breaks from forming in the first place.
When either protein is missing or defective, cells fall back on error-prone repair methods. Mistakes accumulate with each round of cell division. Over years and decades, this genomic instability can transform a normal cell into a cancerous one.
How BRCA Mutations Are Inherited
BRCA mutations follow an autosomal dominant inheritance pattern. If one of your parents carries a mutation in BRCA1 or BRCA2, you have a 50% chance of inheriting it. The mutation can come from either your mother or your father, and it affects people of all sexes, though the specific cancer risks differ.
You’re born with one working copy and one mutated copy of the gene. Cancer develops when the remaining working copy in a particular cell gets damaged through normal wear and tear over a lifetime. This “two-hit” process is why not every carrier develops cancer, and why cancers tied to BRCA mutations typically appear in adulthood rather than childhood.
In the general population, roughly 1 in 400 people carries a BRCA mutation. In Ashkenazi Jewish populations, the frequency is significantly higher, about 1 in 50 (approximately 2%), due to three specific founder mutations that became common through population bottlenecks centuries ago.
Cancer Risks for Women
The most well-known risk is breast cancer. More than 60% of women who inherit a harmful BRCA1 or BRCA2 mutation will develop breast cancer during their lifetime, compared to about 13% of women in the general population. BRCA1 mutations tend to produce breast cancers that are triple-negative, a subtype that doesn’t respond to hormone-blocking therapies and historically has been harder to treat.
Ovarian cancer risk is also substantially elevated. BRCA1 carriers face a lifetime ovarian cancer risk of roughly 40 to 50%, while BRCA2 carriers face a risk of about 10 to 20%. In the general population, the lifetime risk is under 2%. Ovarian cancer linked to BRCA mutations often develops earlier than typical ovarian cancer and can be difficult to detect because there is no reliable early screening test for it.
Cancer Risks for Men
Men with BRCA mutations face their own set of elevated risks, though awareness has historically lagged behind. Prostate cancer is the primary concern. A BRCA2 mutation can increase prostate cancer risk by roughly five to nine times, with lifetime estimates ranging from 27% to 60% depending on the study population. BRCA1 carriers face a smaller but still meaningful increase, with lifetime prostate cancer risk estimated at 15 to 45%. BRCA2-associated prostate cancers also tend to be more aggressive, appearing at younger ages and progressing more quickly.
Pancreatic cancer risk rises as well, though the absolute numbers remain lower. BRCA2 carriers have a lifetime pancreatic cancer risk of up to 7%, compared to roughly 1.5% in the general population. For BRCA1 carriers, the lifetime risk is around 3%. Male carriers also have an increased risk of breast cancer, which is rare in men overall but occurs at notably higher rates in BRCA2 carriers.
Testing and Who Should Consider It
Genetic testing for BRCA mutations involves a blood or saliva sample. Results typically take a few weeks. Testing is most commonly recommended for people with a strong family history of breast, ovarian, prostate, or pancreatic cancer, particularly when cancers appeared at young ages or multiple relatives on the same side of the family were affected.
Certain patterns raise suspicion: breast cancer before age 50, ovarian cancer at any age, male breast cancer, multiple breast cancers in the same person, or a known BRCA mutation in a close relative. People of Ashkenazi Jewish descent are often encouraged to consider testing even without a dramatic family history, given the higher carrier frequency in that population.
A positive result doesn’t mean cancer is inevitable. It means your risk is significantly higher than average and that specific steps can reduce that risk. A negative result in someone whose family member tested positive is genuinely reassuring. A negative result without a known family mutation is harder to interpret, because it doesn’t rule out other genetic risk factors.
Screening for Carriers
Women who test positive for a BRCA mutation enter an intensified screening schedule designed to catch cancers as early as possible. Current guidelines recommend annual breast MRI starting at age 25. At age 30, annual mammograms are added, often alternating with MRI every six months so that some form of imaging happens twice a year. Standard screening mammograms, which typically begin at age 40 for average-risk women, aren’t sensitive enough on their own for BRCA carriers, partly because these women are younger and often have denser breast tissue.
For men with BRCA2 mutations, prostate cancer screening with PSA testing generally begins earlier than it would for average-risk men, often starting around age 40. Pancreatic cancer screening is sometimes offered to carriers with a family history of the disease, though protocols are still being refined.
Options for Reducing Risk
The most effective risk-reduction strategy for breast cancer is preventive bilateral mastectomy, which removes both breasts before cancer develops. This surgery reduces breast cancer risk by at least 95% in BRCA carriers. It’s a major decision with significant physical and emotional implications, and many carriers choose enhanced screening instead, or delay surgery until after childbearing years.
Preventive removal of the ovaries and fallopian tubes (salpingo-oophorectomy) addresses ovarian cancer risk directly, and is generally recommended for BRCA carriers between ages 35 and 40, or once childbearing is complete. Because ovarian cancer lacks a reliable screening method and is often caught at advanced stages, this surgery carries particular weight. It also reduces the risk of dying from any cause after a breast cancer diagnosis by more than half, likely because it eliminates a major source of estrogen that can fuel certain breast cancers.
Not every carrier opts for surgery. Some choose medications that lower estrogen levels, while others rely on close surveillance. The right approach depends on which gene is affected, your specific family history, your age, and your personal priorities. These decisions are typically made with the guidance of a genetic counselor and an oncology team who can walk through the numbers for your individual situation.