What BRCA Genes Actually Do
Every cell in your body contains genes that act as instruction sets for normal function. BRCA1 and BRCA2 — short for Breast Cancer gene 1 and Breast Cancer gene 2 — play a particularly important protective role: they help repair breaks in DNA before damaged cells can multiply unchecked. Think of them as the body's quality-control editors, catching errors that could otherwise lead to cancer.
When these genes are working properly, they help keep cell division orderly and controlled. When a pathogenic variant is present, that repair function is compromised. Cells with unrepaired DNA damage are more likely to grow abnormally, which is why BRCA variants are associated with elevated cancer risk.
It is worth emphasizing that most breast and ovarian cancers are not caused by inherited BRCA variants. According to the National Cancer Institute, inherited BRCA variants account for roughly 5–10% of breast cancers and 10–15% of ovarian cancers in the United States. Understanding this context helps prevent unnecessary alarm while still taking hereditary risk seriously. For a broader view of how genes and environment interact in cancer, see modifiable vs. non-modifiable cancer risk factors.
What a BRCA Variant Means for Cancer Risk
Not all BRCA variants carry the same implications. Scientists classify gene changes on a spectrum from benign to pathogenic (harmful). Only pathogenic or likely pathogenic variants are linked to meaningfully higher cancer risk. A variant of uncertain significance (VUS) — a common result — means researchers do not yet have enough data to know whether it affects health.
5–10%
Breast cancers linked to inherited BRCA variants
According to the National Cancer Institute, inherited BRCA1 or BRCA2 variants account for an estimated 5–10% of all breast cancers diagnosed in the US.
~12%
Average lifetime breast cancer risk in the general population
The National Cancer Institute estimates the average American woman has about a 13% (roughly 1 in 8) lifetime chance of developing breast cancer, a baseline against which BRCA-related risk is often compared.
50%
Chance each child inherits a parent's BRCA variant
Because BRCA variants follow an autosomal dominant inheritance pattern, each biological child of a carrier has approximately a 50% chance of inheriting the variant, regardless of sex.
For carriers of confirmed pathogenic BRCA1 variants, lifetime breast cancer risk estimates have ranged from approximately 50–72% in research studies, compared with roughly 12% in the general population. BRCA2 variants carry somewhat lower but still elevated estimates. Ovarian cancer risk also rises substantially, particularly with BRCA1 variants. It is important to understand that these are population-level estimates; individual risk depends on additional factors including overall family history and other genetic influences.
Beyond breast and ovarian cancers, BRCA2 variants are also associated with elevated risks of prostate cancer and pancreatic cancer. These connections matter for male relatives of carriers as well. Cancer risk and genetics for older adults explores this family-wide dimension in greater depth.
Genetic Testing and Counseling: What to Expect
BRCA testing involves analyzing a blood or saliva sample for variants in the BRCA1 and BRCA2 genes. Testing is not appropriate for everyone — it is most meaningful for people with a personal or family history that suggests elevated hereditary risk. A genetic counselor can assess whether testing is appropriate, explain what results mean, and help families navigate the emotional and practical implications.
Prepare Questions Before Your Genetic Counseling Appointment
Write down your family health history before meeting with a genetic counselor — including cancer diagnoses, ages at diagnosis, and which relatives were affected on both sides of your family. The more detail you can share, the more accurately a counselor can assess your risk and guide you. Many hospital systems and cancer centers offer genetic counseling services; your primary care provider can provide a referral.
Genetic counseling is strongly recommended both before testing — to understand what you are signing up for — and after receiving results, regardless of whether they are positive, negative, or uncertain. A negative result in a family with a known pathogenic variant is genuinely reassuring; a negative result without a known family variant does not eliminate all hereditary risk.
If you are unsure whether your family history warrants a conversation about testing, hereditary cancer syndromes and what family history means offers a useful starting framework. Federal law (GINA) also provides some protections against genetic discrimination by health insurers and employers, though protections are not absolute in all settings.
Living With a BRCA Variant: Proactive Steps
A positive BRCA result is not a passive sentence. It is an opportunity to work with healthcare providers on a personalized management plan. Options generally fall into three categories: enhanced surveillance, chemoprevention, and risk-reducing surgery. The right combination depends on which gene is involved, the specific variant, individual health factors, and personal preferences.
Enhanced surveillance typically means earlier and more frequent screening — such as annual breast MRI alongside mammography, starting at a younger age than standard guidelines recommend. For ovarian cancer, monitoring options are more limited, which is why counseling about prevention strategies is particularly important for BRCA1 carriers.
Whatever path a carrier takes, the goal is informed, proactive decision-making — not reactive fear. Genes influence risk, but they do not write a fixed future. For a grounded perspective on what genetic risk actually means day to day, what your genes actually tell you about disease risk is a helpful companion read.
This article is for general informational and educational purposes only and does not constitute medical advice. If you have concerns about your personal cancer risk or family history, please consult a qualified healthcare professional or certified genetic counselor.
