# MT-CYB

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

## TL;DR

MT-CYB (Cytochrome b) is a gene. In the public catalogues the evidence so far is association rather than a proven role.

## Summary

Component of the ubiquinol-cytochrome c reductase complex (complex III or cytochrome b-c1 complex) that is part of the mitochondrial respiratory chain. The b-c1 complex mediates electron transfer from ubiquinol to cytochrome c. Contributes to the generation of a proton gradient across the mitochondrial membrane that is then used for ATP synthesis.

Open Targets scores its association with cancer at 0.52 (direct and indirect evidence; datatypes literature 0.29, genetic association 0.84).

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: mitochondrially encoded cytochrome b; Cytochrome b; UQCR3; MTCYB
- Tags: cancer-genes-wave
- Symbol: MT-CYB
- Class: other
- Biology: Component of the ubiquinol-cytochrome c reductase complex (complex III or cytochrome b-c1 complex) that is part of the mitochondrial respiratory chain. The b-c1 complex mediates electron transfer from ubiquinol to cytochrome c. Contributes to the generation of a proton gradient across the mitochondrial membrane that is then used for ATP synthesis. Location: Mitochondrion inner membrane (UniProt). Locus mitochondria (HGNC).

## 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: none stated by the sources. Evidence tier "association-only" is the strongest of those signals.
- Prevalence not recorded: none of the sources gives a positivity rate.

## Sources

- HGNC HGNC:7427: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:7427
- UniProt P00156: https://www.uniprot.org/uniprotkb/P00156/entry
- NCBI Gene 4519: https://www.ncbi.nlm.nih.gov/gene/4519
- Ensembl ENSG00000198727: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000198727

## Connected records

- collections: [Open Targets Platform](https://onco.cc/collections/open-targets/)

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JSON: https://onco.cc/api/v1/entities/mt-cyb.json