MSI / MMR
Other names: MSI-high, dMMR, mismatch repair, instabilitas mikrosatelit
MSI/MMR status reflects DNA repair function in the tumour and can open an immunotherapy category.
Not a diagnosis and not final medical advice. Must be reviewed by a doctor.
Plain explanation
Cells have a DNA repair system. When this system does not work (dMMR), DNA becomes unstable (MSI-high). This condition can be discovered through tissue examination.
Clinical meaning
Tumors with MSI-high or dMMR are generally discussed in the immunotherapy category, and some cancers are also directed to evaluation of genetic risk in the family.
Testing methods
- MMR immunohistochemistry
A test of four DNA repair proteins to assess dMMR status.
- MSI PCR
A molecular test to assess microsatellite instability.
- Next-generation sequencing (NGS)
A test that reads many genes from one tumour sample to find actionable changes.
- Tumour tissue biopsy
Collection of tumour tissue to confirm the diagnosis and provide material for further testing.
A negative result does not always mean the marker is absent
Test sensitivity differs by sample type and method. Results need to be read together with the pathology report and clinical condition.
What needs verification
- Whether the examination uses MMR immunohistochemistry or MSI PCR, and the results.
- Are there any indications for genetic counseling in patients and families.
- Family history of cancer that needs to be conveyed.
- Compliance of results with the treatment plan being discussed.
Related drugs
- Pembrolizumab
Anti-PD-1 antibodies
- Nivolumab
Anti-PD-1 antibodies
- Ipilimumab
Anti-CTLA-4 antibodies
- Dostarlimab
Anti-PD-1 antibodies
A link here means the marker is often part of considering a drug category, not a recommendation to use it.
Guides discussing this marker
- CLDN18.2-positive gastric cancer: what does the result mean?9 min read
- Understanding biomarkers without heavy jargon7 min read
- Reading a pathology report: which parts matter most6 min read
Written to help prepare questions and documents, not to replace a doctor's assessment.
Clinical trials
Studies mentioning this marker
Filtered from public study descriptions. Access status and site readiness remain unverified.
NCT05086692Phase 1 / Phase 2Combination regimen
A Beta-only IL-2 ImmunoTherapY Study
Stomach Cancer | biomarker: MSI / MMR | Immunotherapy, Targeted therapy
United States, Australia, Canada +528 registry sites
Why this appears: Appears because it is recorded for Stomach Cancer, it mentions marker MSI / MMR, the treatment category is Immunotherapy.
What to verify: Acceptance of patients from outside the local country has not been verified.
- Registry
- Recruiting in registry
- Site
- Not verified
- International access
- Unknown
- Patient match
- Not assessed
Last checked 16 Oktober 2026Source ClinicalTrials.govNCT05086692Not verified
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Share the MSI / MMR result you have so we can explain which categories to discuss with a doctor.
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Next steps
These suggestions come from links between entries in TanyaKanker's database, not from a medical judgement. Each suggestion includes why it appears.
Next to learn
- Liver Cancer
Subtype
Reason: Related through a biomarker
- Colorectal Cancer
Cancer type
Reason: Related through a biomarker
- Stomach Cancer
Cancer type
Reason: Related through a biomarker
- Gastric cancer after chemotherapy no longer gives results
Decision situation
Reason: Related through a biomarker
- Lung cancer progression after immunotherapy
Decision situation
Reason: Related through a biomarker
- MSI-high or dMMR
Molecular alteration
Reason: Related through a biomarker
To check
- Tumour tissue biopsy
Diagnostic test
Reason: Diperiksa melalui
- MMR immunohistochemistry
Diagnostic test
Reason: Diperiksa melalui
- Next-generation sequencing (NGS)
Diagnostic test
Reason: Diperiksa melalui
- MSI PCR
Diagnostic test
Reason: Diperiksa melalui
- Check medical report completeness
Tool
Reason: Prepare documents that still need confirmation
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Reason: Bring clear questions to the next conversation
What you can do
- Upload medical reports
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Reason: Often the most useful next step after reading this page
- Request a second opinion
Review of the treatment plan
Reason: Relevant when a treatment plan is being considered
- Consult a navigator
A request is recorded with this page context
Reason: For asking the next step directly
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