# MSH3

Source: https://onco.cc/targets/msh3/  
OnCo record `msh3` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

MSH3 (DNA mismatch repair protein Msh3) is a gene. The public catalogues list it as a drug target, a biomarker and a DNA repair gene, and clinical evidence ties its variants to diagnosis, prognosis or drug response. Tied to Endometrial cancer and Colorectal cancer.

## Summary

Component of the post-replicative DNA mismatch repair system (MMR). Heterodimerises with MSH2 to form MutS beta which binds to DNA mismatches thereby initiating DNA repair. When bound, the MutS beta heterodimer bends the DNA helix and shields approximately 20 base pairs.

CIViC holds 1 clinical evidence item and 0 assertions across 1 variant, naming 7-Ethyl-10-Hydroxycamptothecin and Oxaliplatin. Open Targets scores its association with cancer at 0.71 (direct and indirect evidence; datatypes genetic literature 0.49, affected pathway 0.61, literature 0.93, genetic association 0.92, somatic mutation 0.58, animal model 0.45).

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: mutS homolog 3; DNA mismatch repair protein Msh3; MRP1
- Tags: cancer-genes-wave
- Symbol: MSH3
- Class: other
- Biology: Component of the post-replicative DNA mismatch repair system (MMR). Heterodimerises with MSH2 to form MutS beta which binds to DNA mismatches thereby initiating DNA repair. When bound, the MutS beta heterodimer bends the DNA helix and shields approximately 20 base pairs. MutS beta recognises large insertion-deletion loops (IDL) up to 13 nucleotides long. After mismatch binding, forms a ternary complex with the MutL alpha heterodimer, which is thought to be responsible for directing the downstream MMR events, including strand discrimination, excision, and resynthesis. Locus 5q14.1 (HGNC).
- Where found: Endometrial cancer: Open Targets association 0.69 with endometrial cancer (MONDO_0011962); Colorectal cancer: CIViC evidence names this disease

## Notes

- Written by scripts/fetch-cancer-genes.ts from CIViC, Open Targets, IntOGen, HGNC and UniProt; the function text is UniProt's, condensed and in UK spelling. Roles: CIViC lists 2 therapies; CIViC holds 1 clinical evidence items on its variants; UniProt keyword "DNA repair". Evidence tier "clinical-evidence" is the strongest of those signals.
- Prevalence not recorded: none of the sources gives a positivity rate.

## Sources

- HGNC HGNC:7326: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:7326
- UniProt P20585: https://www.uniprot.org/uniprotkb/P20585/entry
- NCBI Gene 4437: https://www.ncbi.nlm.nih.gov/gene/4437
- Ensembl ENSG00000113318: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000113318

## Connected records

- collections: [CIViC](https://onco.cc/collections/civic/), [Open Targets Platform](https://onco.cc/collections/open-targets/)
- cancers: [Colorectal cancer](https://onco.cc/cancers/colorectal/), [Endometrial cancer](https://onco.cc/cancers/endometrial/)

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JSON: https://onco.cc/api/v1/entities/msh3.json