BRCA1 and BRCA2 in Prostate Cancer

Section Editor: Trevor Flood MD FRCPC
May 26, 2026

BRCA1 and BRCA2 are genes whose normal job is to repair damaged DNA and prevent cells from becoming cancerous. When one of these genes carries a harmful mutation, meaning a change in the gene’s DNA sequence that stops it from working the way it should, that protective function is lost, and the risk of developing certain cancers rises significantly. In prostate cancer, BRCA2 mutations in particular are associated with cancers that tend to grow faster, spread earlier, and respond differently to treatment than most prostate cancers. Testing for BRCA1 and BRCA2 mutations is now a standard part of care for many men with prostate cancer: a positive result can identify eligibility for targeted therapies, guide decisions about the extent of treatment, and reveal inherited cancer risk that may affect close relatives.

This article explains what BRCA1 and BRCA2 testing looks for, why it is done in prostate cancer, how the testing is performed, how results are reported, and what a result means for treatment and for you and your family.

What the test looks for

Every person is born with two copies of each gene, one inherited from each parent. BRCA1 and BRCA2 are tumor suppressor genes: their normal role is to detect and repair breaks in DNA. When one copy of BRCA1 or BRCA2 carries a harmful mutation and the second copy is later lost or damaged in a prostate cell, that cell can no longer repair DNA properly. Without this repair function, the cell accumulates additional changes that can lead to cancer.

BRCA1 and BRCA2 mutations in prostate cancer come in two forms, and understanding which form is present matters for interpreting the result:

Germline mutations (hereditary). A germline mutation is one that was present in the egg or sperm cell at conception and is therefore carried in every cell of the body from birth. A person with a germline BRCA1 or BRCA2 mutation inherited it from one of their parents and has a 50% chance of passing it to each of their children. Germline mutations are identified through a blood or saliva test, not through the tumor itself. They are the basis of hereditary breast and ovarian cancer (HBOC) syndrome and carry implications not only for the patient but for biological relatives.
Somatic mutations (acquired). A somatic mutation is one that arose during a person’s lifetime, only within the cancer cells themselves. It was not inherited and cannot be passed to children. Somatic BRCA1 or BRCA2 mutations are identified through testing of the tumor tissue. They are relevant for treatment, particularly for PARP inhibitor eligibility, but they do not carry the same hereditary implications as germline mutations.

In prostate cancer, approximately 5–9% of patients have a germline BRCA1 or BRCA2 mutation, and a further 5–9% have a somatic BRCA mutation in the tumor itself. The two groups partly overlap, meaning that when a somatic mutation is found on tumor testing, germline testing is typically recommended to determine whether the mutation was also inherited.

Why the test is done

To determine eligibility for PARP inhibitor therapy. PARP inhibitors are drugs that exploit a cancer cell’s inability to repair DNA when BRCA function is lost. When a cell with a BRCA mutation is treated with a PARP inhibitor, its DNA repair pathways are so severely compromised that the cell cannot survive. This targeted approach is called synthetic lethality. Olaparib (Lynparza) and rucaparib (Rubraca) are approved for men with BRCA1 or BRCA2 mutations and metastatic castration-resistant prostate cancer. Metastatic means the cancer has spread beyond the prostate to other parts of the body, such as the bones or lymph nodes. Castration-resistant means the cancer has continued to grow despite treatment that lowers testosterone, the hormone that normally fuels prostate cancer growth. Olaparib (in combination with abiraterone) is also approved for certain patients with high-risk metastatic castration-sensitive prostate cancer, meaning cancer that has spread but still responds to testosterone-lowering treatment. Knowing BRCA status is required before these drugs can be considered.
To identify cancers that may respond to platinum-based chemotherapy. Prostate cancers with BRCA mutations, particularly BRCA2, may be more sensitive to platinum-based chemotherapy drugs such as carboplatin. BRCA status may therefore inform chemotherapy selection in some patients with advanced disease.
To assess prognosis. Prostate cancers arising in men with germline BRCA2 mutations tend to be diagnosed at a higher Gleason grade, present at a later stage, and have a higher risk of spreading to lymph nodes and distant sites. This information is relevant for understanding how the cancer is likely to behave and for planning appropriate treatment intensity.
To assess hereditary cancer risk. A confirmed germline BRCA1 or BRCA2 mutation means the patient was born with an inherited predisposition to cancer that may affect other organs and may have been passed to biological relatives. BRCA2 mutations elevate the risk of pancreatic cancer, male breast cancer, and melanoma in addition to prostate cancer. BRCA1 mutations carry a more modest elevation in prostate cancer risk but significant risks for breast and ovarian cancer in female relatives. Identifying the mutation enables relatives to undergo targeted genetic testing and, if positive, to begin appropriate surveillance.
To enable cascade testing of family members. When a germline BRCA mutation is identified, first-degree relatives (parents, siblings, and children) each have a 50% chance of carrying the same mutation. Knowing the specific family mutation allows relatives to have targeted testing and, if positive, to take steps that may reduce their own cancer risk.

Who should be tested

Guidelines have expanded significantly regarding which men with prostate cancer should be offered BRCA testing. Current major oncology guidelines recommend germline testing for:

Men with metastatic prostate cancer (cancer that has spread beyond the prostate), regardless of family history.
Men with high-risk, very high-risk, or locally advanced prostate cancer. This typically means a Grade Group of 3 or higher. The Grade Group is a score from 1 to 5 that describes how abnormal the cancer cells look under the microscope and how likely the cancer is to grow and spread, with higher numbers indicating faster-growing cancers.
Men whose biopsy shows an intraductal or cribriform pattern. Intraductal carcinoma refers to cancer cells growing inside the prostate’s normal duct structures, and a cribriform pattern describes cancer cells arranged in sheets punctured by many small round holes, like a sieve. Both of these microscopic patterns are associated with a higher rate of BRCA2 mutations.
Men with a personal or family history of breast cancer, ovarian cancer, pancreatic cancer, or other BRCA-associated cancers in first- or second-degree relatives.
Men of Ashkenazi Jewish ancestry, in whom founder mutations in BRCA1 and BRCA2 occur at substantially higher rates than in the general population.
Men with a known BRCA mutation in a first-degree relative.

Many guidelines now recommend germline BRCA testing for all men with newly diagnosed prostate cancer who may at some point require systemic therapy, given that the result directly affects treatment options if the cancer progresses. Your oncologist or urologist will advise whether testing is appropriate in your specific situation.

Somatic (tumor) testing is typically recommended when germline results are unavailable and treatment eligibility decisions need to be made, or as part of comprehensive tumor molecular profiling in advanced or metastatic disease.

How the test is performed

Germline testing

Germline BRCA1/2 testing is performed on a blood or saliva sample, not on tumor tissue. DNA extracted from normal blood cells, which carry the patient’s inherited genetic code, is sequenced to identify mutations in the BRCA1 and BRCA2 genes. This testing is arranged through a genetic counselor, urologist, or oncologist. Results generally take two to four weeks.

Germline testing may be limited to BRCA1 and BRCA2 alone, or it may be performed as part of a broader multi-gene panel that simultaneously examines dozens of genes associated with hereditary cancer risk, including ATM, PALB2, CHEK2, CDK12, and others. Multi-gene panels increase the chance of finding a hereditary explanation but also increase the likelihood of identifying variants of uncertain significance (discussed below).

Somatic (tumor) testing

Somatic BRCA testing is performed on tumor tissue, either from a biopsy sample or from the surgical specimen after the prostate has been removed. It uses next-generation sequencing (NGS), a technique that reads the DNA from the cancer cells and identifies mutations. Somatic testing is typically ordered by the oncologist when comprehensive molecular profiling is needed, particularly in men with advanced or metastatic disease.

A somatic BRCA mutation found on tumor testing does not confirm the presence of a germline mutation — but it can serve as a flag. When a somatic BRCA mutation is found, germline testing is recommended to determine whether the mutation was inherited.

How results are reported

BRCA1/2 test results are reported using the American College of Medical Genetics and Genomics (ACMG) five-tier classification system:

Pathogenic variant (Class 5) — A mutation that is clearly harmful. It is known to disrupt the function of the BRCA1 or BRCA2 protein and significantly increases cancer risk. This is what is commonly referred to as “testing positive” for a BRCA mutation. Referral to a genetic counselor and discussion of implications for treatment and family members are required.
Likely pathogenic variant (Class 4) — A mutation that is almost certainly harmful based on current evidence, though not yet confirmed beyond doubt. Managed clinically the same as a pathogenic variant in most cases.
Variant of uncertain significance (VUS) (Class 3) — A change in the gene sequence whose effect on protein function is not yet known. A VUS is neither a positive nor a negative result and cannot be used to make clinical decisions in either direction. VUS results are common, particularly with multi-gene panel testing. Laboratories reclassify VUS results as evidence accumulates, and clinical action should not be taken based solely on a VUS.
Likely benign variant (Class 2) — A variant that is almost certainly not harmful. No action is required.
Benign variant (Class 1) / No pathogenic variant detected — No harmful mutation was found in the genes tested. This substantially reduces, but does not eliminate, hereditary cancer risk, because not all hereditary prostate cancer risk genes have yet been identified.

What each result means

Pathogenic or likely pathogenic germline BRCA2 mutation. This is the most clinically significant result in prostate cancer. Men with germline BRCA2 mutations have a 2–8-fold elevated lifetime risk of developing prostate cancer compared to the general population, and the cancers that develop tend to be higher grade and more likely to spread. For men already diagnosed, the result indicates potential eligibility for PARP inhibitor therapy (in appropriate disease settings), may prompt consideration of platinum chemotherapy, and informs discussions about the intensity of local and systemic treatment. It also triggers a cascade: biological relatives should be offered testing, as each first-degree relative has a 50% chance of carrying the mutation. Female relatives carrying the mutation are at significantly elevated risk of breast and ovarian cancer.
Pathogenic or likely pathogenic germline BRCA1 mutation. BRCA1 mutations carry a more modest elevation in prostate cancer risk than BRCA2, and the evidence for their role in driving more aggressive prostate cancer is less strong than for BRCA2. However, BRCA1 mutations still confer some increased risk and may have treatment-decision implications. More importantly, a germline BRCA1 mutation has major implications for female relatives, who are at substantially elevated risk of breast and ovarian cancer. Family cascade testing and genetic counseling are essential.
Somatic BRCA1 or BRCA2 mutation (tumor only). The mutation is present in the cancer cells but was not inherited. It does not increase the patient’s risk of other cancers, and it cannot be passed to family members. However, somatic BRCA mutations may still predict sensitivity to PARP inhibitors, and clinical trials and some approval pathways include somatic mutations alongside germline mutations. Germline testing should be performed to confirm that the mutation is truly somatic.
Variant of uncertain significance (VUS). No clinical action should be taken based on a VUS alone. It does not confirm hereditary risk and should not be used to guide treatment or surgical decisions. Genetic counseling is strongly recommended. The laboratory will notify the ordering clinician if the variant is reclassified in the future.
No pathogenic variant detected (negative). No BRCA1 or BRCA2 mutation was found. BRCA-specific treatment implications do not apply, though other genes assessed on multi-gene panels (such as ATM or CDK12) may still have clinical relevance. A negative BRCA result does not rule out a hereditary basis for the cancer if other clinical features suggest it; discussion with a genetic counselor may still be worthwhile.

BRCA2 and prostate cancer prognosis

Prostate cancers in men with germline BRCA2 mutations are more likely to present at a higher Gleason score, involve extraprostatic extension (cancer growing beyond the outer edge of the prostate into surrounding tissue), involve seminal vesicle invasion (cancer spreading into the seminal vesicles, the paired glands behind the prostate that help produce semen), and have a higher risk of lymph node involvement and distant spread. Studies have shown that men with germline BRCA2 mutations have a shorter time from diagnosis to metastasis and shorter overall survival than men without BRCA mutations when treated with standard approaches. This prognostic context supports the importance of earlier genetic testing and more intensive treatment planning for BRCA2 carriers.

The prognostic significance of germline BRCA1 mutations in prostate cancer is less clearly established; the evidence is less consistent than for BRCA2. Somatic BRCA mutations also appear to be associated with more advanced disease features, though the evidence base is smaller than for germline mutations.

Other DNA repair genes relevant to prostate cancer

While this article focuses on BRCA1 and BRCA2, it is worth noting that prostate cancer is associated with mutations in a broader set of DNA repair genes beyond BRCA. Other genes, including ATM, CDK12, PALB2, CHEK2, and the mismatch repair genes MLH1, MSH2, MSH6, and PMS2, can also be mutated in prostate cancer and have their own treatment and hereditary implications. When comprehensive tumor molecular profiling or multi-gene germline panel testing is performed, these genes may also be reported. Your oncologist and genetic counselor can explain what the results from any other gene tests mean for your care.

The role of genetic counseling

Genetic counseling is strongly recommended before and after germline BRCA testing. A genetic counselor can help assess your personal and family history to determine which genes are most relevant to test, explain what a positive, negative, or uncertain result means before testing occurs so you are prepared, discuss the emotional and familial dimensions of a positive result (including the decision of whether and how to share results with relatives), coordinate cascade testing for family members once a mutation is identified, and review results and updated interpretations when a VUS is reclassified over time.

Referrals to hereditary cancer programs and genetic counselors are available through most cancer centers. Depending on the clinical setting and jurisdiction, genetic counseling and testing may be covered by provincial or private insurance for patients who meet referral criteria. The article Understanding Genetic Testing in Cancer on this site provides a broader introduction to germline and somatic testing concepts.

What happens next

If a pathogenic germline BRCA2 mutation is found, your oncologist will assess whether your disease stage and prior treatment history make you eligible for a PARP inhibitor. You should request a referral to a genetic counselor if you have not already seen one. A plan to notify and arrange testing for biological relatives should be discussed. Female relatives should be informed promptly, as a BRCA2 mutation significantly elevates their risk of breast and ovarian cancer.
If a pathogenic germline BRCA1 mutation is found, the implications for prostate cancer treatment are more limited than for BRCA2, but genetic counseling and cascade family testing are still important given the major implications for female relatives.
If a somatic BRCA mutation is found on tumor testing, germline testing is recommended to determine whether the mutation was inherited. Your oncologist will assess whether PARP inhibitor eligibility applies in your clinical situation.
If a VUS is found, no clinical action is required based on the VUS alone. Genetic counseling is recommended. Watch for updated interpretations from the laboratory as evidence accumulates over time.
If the result is negative, BRCA-directed targeted therapies do not apply at this time. Your oncologist will base treatment decisions on other features of your cancer. If your personal or family history is suggestive of a hereditary cancer syndrome, broader multi-gene panel testing may still be worthwhile.

Questions to ask your doctor

Should I have germline BRCA1/2 testing based on my diagnosis, cancer grade, or family history?
Will my tumor also be tested for somatic BRCA mutations as part of molecular profiling?
If I test positive for a BRCA2 mutation, does this make me eligible for a PARP inhibitor such as olaparib, and at what stage of disease would that apply?
Does my BRCA result change the recommended intensity of my local treatment, such as surgery or radiation?
Does my BRCA result affect whether platinum chemotherapy might be appropriate for me?
If a somatic BRCA mutation is found on my tumor test, does that mean I should also have a blood or saliva germline test?
What other DNA repair genes are being tested alongside BRCA1 and BRCA2, and do those results have implications for my treatment?
Should my close relatives be tested, and how do I arrange that?
What are the cancer risks for my female relatives if I carry a BRCA mutation?
If I received a variant of uncertain significance, what does that mean, and how will I know if its classification changes?
Can you refer me to a genetic counselor?

The information on this page is intended for general informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of your physician or other qualified health provider with any questions you may have regarding your medical condition.