Being BRCA positive means you carry a harmful change, or mutation, in one of two genes called BRCA1 or BRCA2. These genes normally help your cells repair damaged DNA. When one of them isn’t working correctly, your body loses a critical line of defense against cancer, which significantly raises your lifetime risk of developing breast, ovarian, prostate, and several other cancers. About 1 in 200 people in the general population carries a BRCA mutation.
What BRCA Genes Normally Do
Every cell in your body sustains DNA damage on a regular basis, from normal metabolism, environmental exposures, and simple copying errors during cell division. Your body has built-in repair systems to fix this damage before it causes problems. BRCA1 and BRCA2 are central players in one of the most important of these systems, which fixes a specific and dangerous type of DNA break where both strands of the double helix snap apart.
When either gene carries a harmful mutation, that repair pathway doesn’t function properly. Most of the time, other backup systems can compensate. But over a lifetime, the accumulating unrepaired damage increases the odds that a cell will develop the kinds of errors that lead to uncontrolled growth. That’s why carrying a BRCA mutation doesn’t guarantee cancer, but it does raise the probability substantially.
Cancer Risks for Women
The cancers most strongly associated with BRCA mutations are breast and ovarian cancer. Women in the general population have roughly a 13% lifetime risk of breast cancer. For women with a BRCA1 mutation, that risk climbs to around 55 to 72%. BRCA2 carriers face a lifetime breast cancer risk of approximately 45 to 69%. These numbers represent risk by age 70 to 80, and they vary depending on family history and other individual factors.
Ovarian cancer risk is even more dramatically elevated. In the general population, a woman’s lifetime ovarian cancer risk is about 1.2%. BRCA1 carriers face a risk of roughly 39 to 44%, while BRCA2 carriers face a risk of about 11 to 17%. BRCA mutations are also linked to higher rates of pancreatic cancer and, for BRCA2 specifically, melanoma.
Cancer Risks for Men
BRCA mutations aren’t just a women’s health issue. Men who carry these mutations face elevated cancer risks too, particularly for prostate cancer and male breast cancer. About 1.8% to 7.1% of men with a BRCA2 mutation will develop breast cancer by age 70, compared to less than 0.1% of men in the general population. For BRCA1 carriers, the male breast cancer risk is lower, around 0.2% to 1.2%.
Prostate cancer risk is where the numbers get especially notable. Men with BRCA2 mutations have a 19% to 61% chance of developing prostate cancer by age 80. BRCA1 carriers face a 7% to 26% risk over the same time frame. BRCA2-related prostate cancers also tend to be more aggressive and diagnosed at a younger age than typical prostate cancers.
How BRCA Mutations Are Inherited
BRCA mutations follow an autosomal dominant inheritance pattern, which means you only need one copy of the mutated gene (from one parent) for it to affect your cancer risk. If a parent carries a BRCA mutation, each of their children has a 50% chance of inheriting it, regardless of sex. A father can pass a BRCA mutation to his daughter just as a mother can pass it to her son.
Certain populations carry BRCA mutations at much higher rates. People of Ashkenazi Jewish descent (those with Central or Eastern European Jewish ancestry) have a 1 in 40 chance of carrying a BRCA1 or BRCA2 mutation, roughly five times the rate in the general population. Other groups with elevated prevalence include people of Norwegian, Dutch, and Icelandic heritage, though the Ashkenazi population is the most studied.
How Testing Works
BRCA testing is typically a blood or saliva test that analyzes the DNA sequence of both genes. Results generally come back in a few weeks and fall into three categories: positive (a known harmful mutation was found), negative (no mutation detected), or a variant of uncertain significance, meaning a change was found but scientists don’t yet know whether it affects cancer risk. That last result can be frustrating, but as genetic databases grow, many of these variants are eventually reclassified.
Testing is often recommended for people with a strong family history of breast or ovarian cancer, a family member with a known BRCA mutation, a personal history of cancer at a young age, or Ashkenazi Jewish ancestry. Some people pursue testing through direct-to-consumer genetic kits, but these only screen for a handful of the most common mutations and can miss many others. A full clinical test is more comprehensive.
Preventive Options for BRCA Carriers
A positive BRCA result doesn’t mean cancer is inevitable. It means you have options for reducing your risk, and those options can be highly effective. Enhanced screening is the least invasive approach: alternating between mammograms and breast MRIs every six months, starting in your 20s or 30s rather than at the standard age of 40. For ovarian cancer, screening is less reliable, which is why many carriers and their doctors focus on prevention rather than early detection for that particular cancer.
Preventive surgery offers the most dramatic risk reduction. Bilateral mastectomy (removal of both breasts) reduces breast cancer risk by at least 95% in women with BRCA mutations. Preventive removal of the ovaries and fallopian tubes eliminates the vast majority of ovarian cancer risk and, according to some studies, cuts the risk of dying from any cause after a breast cancer diagnosis by more than half. Many carriers choose to have their ovaries removed after finishing childbearing, typically between ages 35 and 45 depending on whether the mutation is in BRCA1 or BRCA2.
These are deeply personal decisions that depend on your specific mutation, your family history, your age, and your priorities. Genetic counselors specialize in walking people through the numbers and helping them understand what each option would look like in practice.
How BRCA Status Affects Cancer Treatment
If you’ve already been diagnosed with cancer, being BRCA positive actually opens the door to a targeted class of drugs called PARP inhibitors. Here’s how they work: your cancer cells already have a broken DNA repair system because of the BRCA mutation. PARP is a protein that cancer cells rely on as a backup repair pathway to stay alive. PARP inhibitors block that backup system, leaving the cancer cells with no way to fix their DNA. The accumulating damage causes the cancer cells to die.
This approach is particularly effective because it exploits the very weakness that made the cells cancerous in the first place. Normal cells in your body still have one working copy of the BRCA gene, so they can tolerate PARP inhibition much better than the tumor can. PARP inhibitors are currently used for certain breast, ovarian, prostate, and pancreatic cancers that involve BRCA mutations, and they’re taken as pills rather than through infusion.
Platinum-based chemotherapy drugs also tend to be more effective in BRCA-positive cancers for similar reasons: they work by damaging DNA, and cancer cells that can’t repair that damage are more vulnerable to it. So while a BRCA mutation increases your risk of getting cancer, it can paradoxically make certain treatments work better if cancer does develop.