The short answer
BRCA1 and BRCA2 are genes that help repair damaged DNA. Inheriting a harmful change in one of them raises the risk of breast, ovarian, and several other cancers, often at younger ages. A positive result does not mean cancer is certain, and many people with these changes never develop cancer. Genetic counseling helps make sense of the risks and options.
BRCA1 and BRCA2 are genes that make proteins that help repair damaged DNA.
An inherited harmful change in one of these genes raises the risk of several cancers.
More than 60 percent of women with a harmful BRCA change develop breast cancer in their lifetime.
These changes also raise the risk of ovarian, prostate, pancreatic, and male breast cancer.
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The full explanation.
The simple version
BRCA1 and BRCA2 are genes that everyone has. Their job is to make proteins that help repair damaged DNA. You carry two copies of each gene — one from each parent.
Some people inherit a harmful change (also called a mutation or pathogenic variant) in one of these genes. That change raises the risk of several cancers, most of all breast and ovarian cancer.
A harmful BRCA change raises cancer risk — but it does not mean cancer is certain.
What the genes normally do
BRCA1 and BRCA2 help keep DNA healthy by fixing damage. Nearly everyone who inherits a harmful change in one gene still has a normal second copy from the other parent, and one working copy is usually enough to protect cells.
But that normal copy can be lost or damaged during a person's life. When a cell loses its only working copy, it can no longer repair DNA well, and it may grow out of control and become cancer. That is why an inherited BRCA change raises risk without guaranteeing disease.
How much risk it adds
The National Cancer Institute reports that the risks are markedly higher for people with a harmful BRCA change:
- Breast cancer: More than 60 percent of women with a harmful BRCA change develop breast cancer in their lifetime, compared with about 13 percent of women in the general population.
- Ovarian cancer: Risk is far higher than the roughly 1 percent seen in the general population, and it differs between BRCA1 and BRCA2.
- Other cancers: Harmful BRCA changes also raise the risk of pancreatic cancer, prostate cancer, and male breast cancer.
People with a harmful BRCA change also tend to develop cancer at younger ages than others.
These are raised risks, not certainties — the numbers describe groups, not any one person.
BRCA changes in men
BRCA changes are not only a concern for women. Men can inherit a harmful change, and it raises their risk of male breast cancer and prostate cancer, with BRCA2 especially linked to prostate cancer. Men can also pass the change to their children, so a father's BRCA status can matter for the whole family.
Who carries these changes
Harmful BRCA changes are rare — about 1 in 400 people in the general population. Some groups have a higher rate. About 2 percent of people of Ashkenazi Jewish descent carry one of three specific changes, called founder mutations. Other populations, including Norwegian, Icelandic, Hispanic, and West African groups, have their own founder mutations. Different groups may carry different changes.
Managing risk (in general terms)
For people known to carry a harmful BRCA change, several options exist to manage risk. These are decisions to make with a care team, and this article does not recommend any path. In general, options can include:
- Enhanced screening, such as starting breast screening younger and adding MRI to mammography
- Risk-reducing surgery, which removes at-risk tissue but has real trade-offs
- Risk-reducing medications in some situations
Each option has benefits and downsides, and no approach removes all risk.
BRCA and treatment
BRCA status can also matter for people who already have cancer. Cancers with harmful BRCA changes may respond to certain DNA-damaging drugs and to a class of medicines called PARP inhibitors. Sometimes a harmful BRCA change is first found when a tumor is tested. Because such a change may be inherited or may have arisen in the tumor, a separate inherited-risk (germline) test can confirm whether it was passed down.
A calm way to think about it
A harmful BRCA change raises risk, but it is not a diagnosis and not a certainty. Testing uses a simple blood or saliva sample, and genetic counseling helps a person understand what a result would mean — for them and for their relatives — before and after any test. Knowing your family's cancer story and sharing it with your care team is the practical first step.
Words to know
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Common questions
▸What are BRCA1 and BRCA2?
BRCA1 and BRCA2 are genes that everyone has, in two copies each — one inherited from each parent. They make proteins that help repair damaged DNA. People who inherit a harmful change in one of these genes have a higher risk of several cancers, most notably breast and ovarian cancer.
▸How much do BRCA changes raise cancer risk?
According to the National Cancer Institute, more than 60 percent of women who inherit a harmful BRCA change develop breast cancer in their lifetime, compared with about 13 percent of women in the general population. Ovarian cancer risk is also markedly higher. Exact risk varies by which gene is affected and other factors.
▸Does a positive result mean I will get cancer?
No. A positive result means a harmful change was found and that cancer risk is increased. It cannot tell whether or when cancer will develop, and some people who inherit a harmful BRCA change never get cancer.
▸Can men have BRCA gene changes?
Yes. Men can inherit and pass on harmful BRCA changes. These raise a man's risk of male breast cancer and prostate cancer, and BRCA2 in particular is linked to higher prostate cancer risk. Men can also pass the change to their children.
▸Who is more likely to carry a BRCA change?
Harmful BRCA changes are found in about 1 in 400 people overall, but some populations have a higher rate. For example, about 2 percent of people of Ashkenazi Jewish descent carry one of a few specific changes called founder mutations. Several other populations also have their own founder mutations.
▸How is testing for BRCA changes done?
Because an inherited change is present in every cell of the body, testing can use a sample of blood or saliva. Genetic counseling is recommended so a person understands what a result would mean for them and their blood relatives before testing.
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