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The RAD51C gene: what it does and why it matters | CION Cancer Clinics
RAD51C is a gene that helps your cells repair broken DNA, working in the same repair system as BRCA1 and BRCA2. A fault in RAD51C raises the risk of ovarian cancer, and to a lesser degree breast cancer. This page explains what the gene does, how a fault turns into risk, and why a result usually calls for careful planning rather than alarm. At CION Cancer Clinics, our oncologists explain what a gene result means for you and your family, and plan the checks that follow.
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Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
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On this page
- What does the RAD51C gene actually do?
- Which cancers does a RAD51C fault affect?
- How does a faulty repair gene lead to cancer?
- What do the words on a RAD51C report mean?
- How is RAD51C different from BRCA1?
- Four things families believe about RAD51C, and what is true
- What this page cannot tell you
- Common questions about the RAD51C gene
The short answer
What does the RAD51C gene actually do?
RAD51C makes a protein that helps repair one of the most serious kinds of DNA damage, where both strands of the DNA snap at the same point. It works as part of a small repair team, alongside the better known BRCA1 and BRCA2. When RAD51C is faulty, that repair is less reliable, and over many years a damaged cell is more likely to slip through.
One of a family of helper genes
RAD51C belongs to a group of genes that help a central repair protein, called RAD51, find the broken ends and copy the missing information from the matching chromosome. RAD51D is a close relative that does a similar job. This is why the two genes are often discussed together and carry a similar pattern of risk.
Why the name is on your report
RAD51C is included in most test panels offered for a family history of ovarian or breast cancer. Many people see the name for the first time on a result. Seeing it listed does not mean the test found cancer. It means the laboratory checked this gene, and possibly found a change it thinks is worth reporting.
A RAD51C fault is a statement about risk. It is not a diagnosis of cancer.Where the risk sits
Which cancers does a RAD51C fault affect?
The picture is clearest for the ovary. For other organs the evidence is thinner, and a good counsellor will say so.
Ovarian cancer
The best established risk. A fault raises lifetime risk well above that of the general population, though most carriers never develop it. Because ovarian cancer is hard to find early, this is the risk that shapes most decisions.
What it usually leads to
- A talk about removing the ovaries and tubes later in adult life
- No reliable screening test to lean on instead
Breast cancer
A moderately raised risk, seen more often in the type called triple-negative. Breast checks are usually planned from your family history as well as from the result itself.
Other cancers
Links to other cancers have been suggested but not confirmed. Studies so far are small. Your plan should not change on the strength of an unproven link.
Men who carry it
A man has no clearly raised cancer risk of his own from a RAD51C fault. He can still pass it to a daughter or a son, which is why men belong in family testing.
Not sure whether this applies to you?
Ask an oncologistFrom fault to risk
How does a faulty repair gene lead to cancer?
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You inherit two copies
One comes from each parent. One working copy of RAD51C is usually enough to keep DNA repair running normally.
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A fault removes one copy from birth
A carrier has one working copy instead of two, in every cell of the body. Nothing is wrong at this stage, and there is nothing to feel.
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The second copy can be lost in one cell
Over decades, the remaining copy can be damaged in a single cell, often in the ovary or the fallopian tube. That cell then struggles to repair broken DNA.
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Mistakes build up
Without good repair, that cell gathers more errors each time it divides. Most such cells are cleared by the body without anyone ever knowing.
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Occasionally a tumour forms
When enough errors land in the wrong genes, a cancer can grow. This usually takes many years, which is why the risk rises mainly in later adult life.
On your report
What do the words on a RAD51C report mean?
- Heterozygous
- One faulty copy and one working copy. This is what almost every RAD51C carrier has.
- Pathogenic variant
- A change known to break the gene. A likely pathogenic result is handled the same way when planning care.
- Variant of uncertain significance
- A change the laboratory cannot yet classify. It should not change your care or lead to surgery.
- Homologous recombination
- The repair system RAD51C belongs to. Your oncologist may use this phrase when talking about treatment.
- Moderate penetrance
- The fault raises risk, but less steeply than a BRCA1 fault. Many carriers never develop cancer.
- Germline
- Present in every cell from birth, and so inheritable. A fault found only inside a tumour is a different matter.
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Side by side
How is RAD51C different from BRCA1?
RAD51C
BRCA1
Ovarian risk raised, but less steeply
Ovarian risk raised steeply
Ovary surgery usually discussed later in life
Ovary surgery usually discussed earlier
Breast risk moderate, planned with family history
Breast risk high, with MRI from young adulthood
Evidence still growing from smaller studies
Decades of evidence from large studies
Commonly believed
Four things families believe about RAD51C, and what is true
"It is a lesser BRCA, so it does not really matter."
The risk is lower than with BRCA1, but it is real, and it sits mostly in the ovary, where early detection is hard. A result deserves a proper plan, even if that plan is calmer and starts later.
"Only the women in the family need to be tested."
A father can pass the fault to a daughter as easily as a mother can. Brothers and sons should be offered testing so that their own daughters have the information when they need it.
"A fault means my ovaries must come out straight away."
Timing depends on your age, whether your family is complete and the pattern of cancer in your family. For most carriers this conversation happens later in adult life, and it is always your choice.
"My tumour test showed nothing, so I do not carry it."
Tumour testing and inherited testing answer different questions. An inherited fault is confirmed from blood or saliva. Testing the tumour itself is covered on our targeted therapy pages.
Being straight with you
What this page cannot tell you
It cannot tell you what your own RAD51C result means. The exact variant, how it is classified and your family history all change the advice. What your specific variant means is a question for the counsellor who ordered the test.
It cannot give you a personal risk figure
Risk estimates for RAD51C come from studies of different sizes and populations, and few of them include Indian families. A counsellor can combine your result with your family tree in a risk tool and give you a figure that fits you better than any average.
Who this does not apply to
If you have not been tested, or your test found no fault in RAD51C, this page is not about you. Most people with one relative who had breast cancer late in life do not need RAD51C testing at all. A counsellor will tell you that honestly.
Bring the full report, not only the first page, when you see the counsellor.Questions we are asked
Common questions about the RAD51C gene
Is RAD51C as serious as BRCA1 or BRCA2?
No. It raises risk less steeply, especially for breast cancer. The ovarian risk is the main concern, and it is large enough that a plan is needed. Your counsellor will explain where your own result sits, using your family history as well as the gene.
Can the ovaries be screened in a RAD51C carrier?
Not reliably. Ultrasound scans and the CA-125 blood test have not been shown to find ovarian cancer early enough to save lives in carriers. This is why the conversation turns to preventive surgery in later adult life rather than to scans.
Does a RAD51C fault change treatment if I already have cancer?
It can. Faults in repair genes may make some ovarian cancers more likely to respond to a group of medicines called PARP inhibitors. Whether that applies to you is decided by your oncologist, who looks at the tumour, the stage and your wider health.
Should my children be tested for RAD51C?
The cancers linked to RAD51C appear in adult life, so testing usually waits until a child is an adult who can decide for themselves. The one situation to raise early is when both parents might carry a fault in this gene.
What if both parents carry a RAD51C fault?
A child who inherits two faulty copies can have a rare, serious childhood condition affecting the bone marrow and growth. This matters most in marriages within the family or a close community. A counsellor can test the partner and explain the options before a pregnancy.
My report shows a RAD51C variant of uncertain significance. What now?
It is not a positive result. Your care should follow your family history, not the variant. Laboratories review these changes as evidence grows, so ask how you will be told if it is ever reclassified.
Does RAD51C matter for men?
A man has no clearly raised cancer risk of his own from this fault. He has a one in two chance of passing it to each child, son or daughter. That is why brothers and sons are part of family testing.
Where do I start after a RAD51C result?
Book a session with a genetic counsellor. Bring the full report and a list of relatives with cancer, with their rough ages at diagnosis. Call the CION helpline if you are unsure where to go. Counselling can be given in Telugu.
Your Specialists
Meet CION's oncologists. Bring your family history or genetic report to them.
Our medical oncologists see people with a strong family history of cancer, arrange genetic counselling and testing where it fits, and plan the checks that follow.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
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Sources
- MedlinePlus Genetics — RAD51C gene
- National Cancer Institute — Genetics of Breast and Gynecologic Cancers (PDQ) - Health Professional Version
- NCCN — Genetic/Familial High-Risk Assessment: Breast, Ovarian, Pancreatic, and Prostate
- National Cancer Institute — Genetic Testing for Inherited Cancer Susceptibility Syndromes
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
RAD51C mutation: which cancers and what riskWhat the raised risk looks like in practiceRAD51C and ovarian risk: why surgery is discussedWhy the ovary shapes most decisionsTesting the family for RAD51CWho else in the family should be offered a testThe RAD51D gene: what it doesThe close relative with a similar pattern of risk
Talk to us
Holding a report that mentions RAD51C?
A genetic counsellor can explain what your result means for you and your family, in Telugu if you prefer. One helpline serves every CION centre.