BRCA1 and BRCA2 are genes that every person has. They produce proteins that repair damaged DNA, acting as tumor suppressors that help prevent cells from growing out of control. When someone inherits a harmful mutation in one of these genes, their body loses a critical line of defense against cancer, significantly raising their lifetime risk of breast, ovarian, and several other cancers.
What BRCA Genes Normally Do
Your cells accumulate DNA damage constantly, from normal metabolism, sunlight, toxins, and simple copying errors during cell division. BRCA1 and BRCA2 proteins are part of the repair crew that fixes double-strand breaks in DNA, the most dangerous type of damage. They do this through a precise process called homologous recombination, which uses an intact copy of the DNA as a template to patch the break accurately.
This repair work is tightly linked to the cell cycle. BRCA1 and BRCA2 expression peaks during S phase, when cells are actively copying their DNA and are most vulnerable to errors. Outside of that window, during rest phases, the body suppresses BRCA production through a chain of well-known tumor suppressor pathways involving p53 and the retinoblastoma protein. This on-off cycling ensures the repair machinery is available exactly when it’s needed most.
When DNA damage is severe, the body deliberately shuts down BRCA expression to force cells out of their growth phase. Without the precision repair tool, the cell switches to cruder, error-prone repair methods that tend to cause so many chromosomal mistakes that the damaged cell dies rather than becoming cancerous. It’s a built-in self-destruct mechanism. But when someone carries a BRCA mutation from birth, this entire system is compromised from the start, and damaged cells are more likely to survive and accumulate the additional mutations that lead to cancer.
How BRCA Mutations Are Inherited
BRCA mutations follow an autosomal dominant inheritance pattern, meaning you only need to inherit one altered copy from one parent to carry the increased risk. Every child of a carrier has a 50% chance of inheriting the mutation. Both men and women can carry and pass on the gene change.
In the general population, roughly 1 in 300 to 1 in 500 people carry a harmful BRCA mutation. The prevalence is notably higher in certain groups. Among people of Ashkenazi Jewish descent, about 1 in 40 carry a BRCA mutation. Three specific mutations account for most of this increased frequency: two in BRCA1 (with carrier rates of about 1.09% and 0.13%) and one in BRCA2 (carrier rate of about 1.52%). Other populations with elevated rates include Norwegian, Dutch, and Icelandic communities, each with their own founder mutations.
Cancer Risks for Women
The most significant risk associated with BRCA mutations is breast cancer. More than 60% of women who inherit a harmful change in either BRCA1 or BRCA2 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 therapies and is generally more aggressive.
Ovarian cancer risk is also dramatically elevated. Women with BRCA1 mutations face a lifetime ovarian cancer risk of roughly 40% to 50%, while those with BRCA2 mutations have a risk of about 10% to 20%. In the general population, the lifetime risk is under 2%. This is especially concerning because ovarian cancer is difficult to detect early and is often diagnosed at advanced stages.
Pancreatic cancer risk rises as well, though to a lesser degree. Women with a BRCA1 mutation have a lifetime pancreatic cancer risk of approximately 2%, and those with a BRCA2 mutation about 3%. While these numbers are modest compared to breast and ovarian risks, they still represent a meaningful increase over the general population’s roughly 1.5% lifetime risk.
Cancer Risks for Men
BRCA mutations are not just a women’s health issue. Men with BRCA2 mutations face a roughly 3.5 times higher risk of prostate cancer than men without the mutation, and the cancers that develop tend to be more aggressive. In one screening study of men with BRCA2 mutations, about 1 in 3 of those with an elevated PSA result were found to have cancer at biopsy. The earliest diagnosis in that study was at age 49, which is why annual screening starting at age 45 has been recommended for male BRCA2 carriers.
Male breast cancer, while rare overall, is also linked to BRCA mutations. By age 70, men with a BRCA2 mutation have a 1.8% to 7.1% chance of developing breast cancer. For BRCA1 carriers, the risk is lower, between 0.2% and 1.2%, but still elevated compared to the general male population risk of less than 0.1%.
Who Should Consider Genetic Testing
BRCA testing became available in 1995 and has expanded significantly since then. Current guidelines don’t recommend testing for everyone. Instead, testing is typically suggested for people whose personal or family history suggests a hereditary cancer pattern. Red flags include breast cancer diagnosed before age 50, ovarian cancer at any age, triple-negative breast cancer, male breast cancer, multiple breast cancers in the same person, or multiple close relatives on the same side of the family with breast, ovarian, pancreatic, or aggressive prostate cancers.
If you have a known BRCA mutation in your family, testing becomes straightforward because the lab can look for that specific change. If no family mutation is known, testing involves sequencing both genes entirely, which occasionally turns up variants of uncertain significance, results that are neither clearly harmful nor clearly harmless. A genetic counselor can help interpret these results and guide next steps.
Screening for Carriers
For women who carry a BRCA mutation and choose not to have risk-reducing surgery, the recommended surveillance schedule is more intensive than standard screening. Current guidelines from the National Comprehensive Cancer Network recommend annual breast MRI with contrast starting at age 25. Beginning at age 30 and continuing until age 75, annual mammograms are added alongside the MRI, creating a schedule where imaging happens roughly every six months, alternating between the two methods.
For ovarian cancer, unfortunately, no screening method has been shown to reliably catch the disease early enough to improve outcomes. This is one reason preventive surgery is discussed as a more definitive option for ovarian cancer risk specifically.
Risk-Reducing Options
Preventive surgery offers the most dramatic risk reduction. Bilateral preventive mastectomy reduces breast cancer risk by at least 95% in women with BRCA mutations. For women who are done having children, removing the ovaries and fallopian tubes reduces ovarian cancer risk by about 80%. This surgery is typically recommended between ages 35 and 40 for BRCA1 carriers and by age 45 for BRCA2 carriers, since BRCA2-related ovarian cancers tend to develop later.
Medications that block or reduce estrogen can also lower breast cancer risk in BRCA carriers, though the risk reduction is less dramatic than surgery. These are sometimes used as a bridge strategy for younger women who aren’t yet ready for surgical options. The choice between enhanced surveillance, medication, and surgery is deeply personal and depends on age, family planning, the specific mutation, and individual priorities. Having a BRCA mutation doesn’t mean cancer is inevitable; it means the risk is high enough to warrant a proactive plan.