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CION Cancer Clinics
PMS2 mutation: which cancers, and how much risk | CION Cancer Clinics
A PMS2 fault mainly raises the risk of bowel cancer and cancer of the womb lining. Both risks are real but lower than with other Lynch syndrome genes, and cancers tend to appear later in life. This page goes organ by organ, explains how strong the evidence is for each, and shows how PMS2 compares with the other Lynch genes. 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
- Which cancers does a PMS2 fault raise the risk of?
- Which organs are affected, and how strong is the evidence?
- How does a PMS2 fault lead to cancer?
- What do the words on a PMS2 report mean?
- How does PMS2 compare with the other Lynch genes?
- What this page cannot tell you
- Four things people believe about PMS2 risk
- Common questions about PMS2 and cancer risk
The short answer
Which cancers does a PMS2 fault raise the risk of?
Mainly bowel cancer and cancer of the womb lining. Both risks are higher than in the general population, but lower than with the other Lynch syndrome genes. Cancers linked to PMS2 also tend to appear later in life.
PMS2 is one of the Lynch syndrome genes
Lynch syndrome is the most common inherited cause of bowel cancer. It is caused by a fault in one of several repair genes. PMS2 is one of them. The others are MLH1, MSH2 and MSH6. Each gene carries its own pattern of risk, and PMS2 carries the mildest.
Why the organ list is shorter than you may have read
Lynch syndrome is linked to cancers in many organs. Most of that long list comes from families with MLH1 and MSH2 faults. For PMS2, the clear evidence points to the bowel and the womb. For other organs the evidence is weak or missing.
Risk is not a diagnosis
Many PMS2 carriers never develop cancer at all. The point of knowing is to find anything early, when it is small and simpler to treat.
What your specific variant means is a question for the counsellor who ordered the test.Organ by organ
Which organs are affected, and how strong is the evidence?
The evidence is not equally strong for every organ. This is roughly how specialists weigh it today.
Bowel
The clearest risk, in men and women. It is raised above the general population, but well below other Lynch genes. Regular colonoscopy can find and remove growths before they turn into cancer.
Womb lining
The main extra risk for women. Cancer here often shows itself early through unusual bleeding. That is why women are taught which bleeding to report straight away.
Report without delay
- Any bleeding after the menopause
- Bleeding between periods
- Periods that suddenly become much heavier
Ovaries
Studies disagree. Some find a small increase and others find none worth acting on. Your counsellor will weigh your own family history before advising anything here.
Other organs
Stomach, small bowel, urinary tract, pancreas and brain are raised with other Lynch genes. For PMS2, studies so far are small and do not show a clear increase. A strong family history of one of these can still change your plan.
Not sure whether this applies to you?
Ask an oncologistHow the risk builds
How does a PMS2 fault lead to cancer?
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PMS2 is a spell-checker for your cells
Every time a cell divides, it copies its DNA. Small copying errors happen. PMS2 works with a partner gene to find and fix those errors before they are passed on.
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You are born with one working copy
A carrier inherits one faulty copy and one working copy. The working copy keeps the repair system running. Most of your cells stay perfectly normal.
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The working copy can fail in one cell
Over many years, the second copy may be damaged in a single cell, often in the bowel or the womb lining. That cell has lost its spell-checker.
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Errors pile up in that cell
Without repair, mistakes build up fast. In the bowel this usually begins as a small growth called a polyp, which can be removed during a colonoscopy.
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Why PMS2 moves more slowly
A partner gene can partly cover for PMS2 when it fails. That may be one reason cancers linked to PMS2 are less common and tend to start later.
On your report
What do the words on a PMS2 report mean?
- Lynch syndrome
- The inherited condition caused by a fault in a mismatch repair gene. PMS2 is one of those genes.
- Mismatch repair
- The cell's system for fixing copying errors in DNA. The four Lynch genes all belong to it.
- Pathogenic variant
- A change known to stop the gene working. This is what a "positive" PMS2 result means.
- Penetrance
- How often a fault actually leads to cancer across everyone who has it. For PMS2 it is lower than for the other Lynch genes.
- Lifetime risk
- The chance of a cancer developing at some point over a whole life. It is an average across many people, not a forecast for you.
- Germline
- Present in every cell from birth and able to pass to children. The opposite, somatic, means a change found only in a tumour.
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Side by side
How does PMS2 compare with the other Lynch genes?
PMS2
MLH1 and MSH2
Bowel risk raised, but the lowest of the group
Bowel risk the highest of the group
Cancers tend to appear later in life
Cancers can appear in young adults
Clear evidence mainly for bowel and womb
Risks spread across many organs
Colonoscopy usually starts later
Colonoscopy starts younger and is more frequent
Being straight with you
What this page cannot tell you
It cannot give you your own number. Published risk figures for PMS2 vary a great deal between studies. Older studies looked mostly at families with many cancers, which pushed the figures up. Newer studies suggest lower risks. Your counsellor will explain which figures apply to you and why.
It cannot read your report
PMS2 is technically hard to test, because a near-copy of the gene sits elsewhere in your DNA and can confuse the laboratory. If your result was unclear, ask whether it has been confirmed by a second method.
Who this does not apply to
This page is for people with a confirmed PMS2 fault in their own blood test. If the fault was found only in a tumour sample, that is a different question. It belongs with your oncologist and the tumour testing team, not with this page.
Commonly believed
Four things people believe about PMS2 risk
"PMS2 is low risk, so I can skip colonoscopy."
Lower is not the same as none. Your bowel risk is still above that of the general population, and colonoscopy is the check that makes the biggest difference.
"Lynch means I will get cancer in every organ on the list."
Most of that list comes from other Lynch genes. For PMS2, the clear risks are in the bowel and the womb. Many carriers never develop cancer anywhere.
"Nobody in our family had bowel cancer, so the result must be wrong."
PMS2 often hides in families. Because its risks are lower and later, many carrier families show no clear pattern at all.
"Men do not need to worry about PMS2."
Men share the raised bowel risk and need colonoscopy too. A man can also pass the fault to his daughters, who have the extra womb risk.
Questions we are asked
Common questions about PMS2 and cancer risk
Is PMS2 the same as Lynch syndrome?
A PMS2 fault is one cause of Lynch syndrome. Lynch syndrome can come from any of several repair genes, and each one carries a different level of risk. PMS2 is the mildest. Your plan should be based on your gene, not on Lynch syndrome in general.
Why do websites give such different risk figures?
Because studies have measured it in different ways. Research on families with a lot of cancer gives high figures. Research across wider populations gives lower ones. Specialists now lean towards the lower estimates for PMS2.
Does PMS2 raise the risk of ovarian cancer?
The evidence is unclear. Some studies suggest a small rise and others do not. Your counsellor will look at whether ovarian cancer has appeared in your family before suggesting anything beyond awareness.
Is my stomach or urinary tract at risk?
For PMS2 on its own, studies so far do not show a clear rise. If a close relative has had one of these cancers, your team may still suggest extra checks. Tell your counsellor about every cancer in the family.
At what age do PMS2 cancers usually appear?
Usually later than with other Lynch genes, often in middle age or beyond. That is why bowel checks tend to begin later for PMS2 carriers. Your team will set a start age that fits your family history.
What should a woman with PMS2 watch for?
Unusual bleeding from the womb. That means any bleeding after the menopause, bleeding between periods, or a sudden change in periods. See a gynaecologist promptly and say you carry a Lynch gene.
Can my children inherit this risk?
Each child has a one in two chance of inheriting the fault. Testing usually waits until they are adults, because checks do not begin in childhood. If both parents carry a Lynch fault, speak to a counsellor before pregnancy.
Does a PMS2 fault change cancer treatment?
It can. Tumours linked to Lynch syndrome often respond well to certain immunotherapy drugs. Whether that applies is decided by testing the tumour itself, which your oncologist arranges separately from this blood test.
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
- GeneReviews (NCBI) — Lynch Syndrome
- MedlinePlus Genetics — PMS2 gene
- National Cancer Institute — Genetics of Colorectal Cancer (PDQ)
- MedlinePlus Genetics — Lynch syndrome
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.
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