# OCA2

Source: https://onco.cc/targets/oca2/  
OnCo record `oca2` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

OCA2 (P protein) is a gene. In the public catalogues the evidence so far is association rather than a proven role. Tied to Skin cancer, Melanoma and Basal cell carcinoma.

## Summary

Contributes to a melanosome-specific anion (chloride) current that modulates melanosomal pH for optimal tyrosinase activity required for melanogenesis and the melanosome maturation. One of the components of the mammalian pigmentary system. May serve as a key control point at which ethnic skin colour variation is determined.

Open Targets scores its association with cancer at 0.64 (direct and indirect evidence; datatypes literature 0.45, animal model 0.63, genetic association 0.76).

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: OCA2 melanosomal transmembrane protein; P protein; BEY1; BEY2; SLC13B1; D15S12; EYCL3; EYCL2
- Tags: cancer-genes-wave
- Symbol: OCA2
- Class: other
- Biology: Contributes to a melanosome-specific anion (chloride) current that modulates melanosomal pH for optimal tyrosinase activity required for melanogenesis and the melanosome maturation. One of the components of the mammalian pigmentary system. May serve as a key control point at which ethnic skin colour variation is determined. Major determinant of brown and/or blue eye colour. Seems to regulate the post-translational processing of tyrosinase, which catalyses the limiting reaction in melanin synthesis. Location: Melanosome membrane (UniProt). Locus 15q12-q13.1 (HGNC).
- Where found: Skin cancer: Open Targets association 0.63 with skin cancer (MONDO_0002898); Melanoma: Open Targets association 0.59 with melanoma (MONDO_0005105); Basal cell carcinoma: Open Targets association 0.54 with basal cell carcinoma (MONDO_0020804)

## 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:8101: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:8101
- UniProt Q04671: https://www.uniprot.org/uniprotkb/Q04671/entry
- NCBI Gene 4948: https://www.ncbi.nlm.nih.gov/gene/4948
- Ensembl ENSG00000104044: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000104044

## Connected records

- collections: [Open Targets Platform](https://onco.cc/collections/open-targets/)
- cancers: [Basal cell carcinoma](https://onco.cc/cancers/basal-cell-carcinoma/), [Melanoma](https://onco.cc/cancers/melanoma/), [Skin cancer (all types)](https://onco.cc/cancers/skin-cancer/)

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JSON: https://onco.cc/api/v1/entities/oca2.json