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DNA Repair· 2 min read

Mismatch-Repair Protein Loss Patterns: What IHC Can Show

Mismatch-repair immunohistochemistry assesses protein expression in tumour tissue. Loss patterns can help direct further testing, but they do not by themselves identify the underlying cause or establish Lynch syndrome.

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Quick Answer

Mismatch-repair immunohistochemistry assesses protein expression in tumour tissue. Loss patterns can help direct further testing, but they do not by themselves identify the underlying cause or establish Lynch syndrome.

Mismatch-Repair Protein Loss Patterns: What IHC Can Show: mechanism and interpretation mapThree connected stages summarise the article's mechanism, measured effect and interpretation boundary.MLH1 · MSH2 · MSH6 · PMS21A Protein-Expression AssayMechanism2Pattern Is a Starting PointObserved consequence3Key TakeawaysInterpret in contextGene or pathway evidence → measured phenotype → assay-aware conclusion
Mechanism map: the article’s main biological stages are separated from the final interpretation so a pathway relationship is not mistaken for a clinical conclusion.

A Protein-Expression Assay

IHC uses staining to assess whether mismatch-repair proteins are detected in tumour cells. Retained staining and loss of staining are technical observations that need pathology-quality controls.

Pattern Is a Starting Point

Protein partners often yield paired patterns, but follow-up may include microsatellite testing, methylation analysis or germline evaluation. The pattern alone is not a diagnosis of inherited disease.

Key Takeaways

  • ·IHC assesses protein expression, not DNA sequence.
  • ·Loss patterns guide further work-up.
  • ·Lynch syndrome requires appropriate confirmatory assessment.

Frequently asked questions

What is the key idea in Mismatch-Repair Protein Loss Patterns: What IHC Can Show?

Mismatch-repair immunohistochemistry assesses protein expression in tumour tissue. Loss patterns can help direct further testing, but they do not by themselves identify the underlying cause or establish Lynch syndrome.

What should be kept with the result or mechanism?

IHC assesses protein expression, not DNA sequence. Loss patterns guide further work-up. Lynch syndrome requires appropriate confirmatory assessment.

References

  1. 1Genetics of colorectal cancer PDQ. National Cancer Institute, 2026. Source
  2. 2Mismatch repair and Lynch syndrome. Nature Reviews Cancer, 2017. PubMed
  3. 3FDA approval for MSI-H/dMMR colorectal cancer. FDA, 2026. Source

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