# ABO

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

## TL;DR

ABO (Histo-blood group ABO system transferase) is an enzyme. In the public catalogues the evidence so far is association rather than a proven role.

## Summary

This protein is the basis of the ABO blood group system. The histo-blood group ABO involves three carbohydrate antigens: A, B, and H. A, B, and AB individuals express a glycosyltransferase activity that converts the H antigen to the A antigen (by addition of N-acetyl-alpha-D-galactosamine (GalNAc)) or to the B antigen (by addition of galactose (Gal)), whereas O individuals lack such activity and express the H antigen precursor unmodified.

Open Targets scores its association with cancer at 0.55 (direct and indirect evidence; datatypes literature 0.85, genetic association 0.68).

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: ABO, alpha 1-3-N-acetylgalactosaminyltransferase and alpha 1-3-galactosyltransferase; Histo-blood group ABO system transferase; A3GALNT; A3GALT1
- Tags: cancer-genes-wave
- Symbol: ABO
- Class: enzyme
- Biology: This protein is the basis of the ABO blood group system. The histo-blood group ABO involves three carbohydrate antigens: A, B, and H. A, B, and AB individuals express a glycosyltransferase activity that converts the H antigen to the A antigen (by addition of N-acetyl-alpha-D-galactosamine (GalNAc)) or to the B antigen (by addition of galactose (Gal)), whereas O individuals lack such activity and express the H antigen precursor unmodified. Catalyses the transfer of GalNAc or Gal in an alpha1,3 linkage to the terminal Gal of all five types of naturally occurring H antigens, forming the antigenic structures of the A and B blood groups. Location: Golgi apparatus, Golgi stack membrane; Secreted (UniProt). Locus 9q34.2 (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:79: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:79
- UniProt P16442: https://www.uniprot.org/uniprotkb/P16442/entry
- NCBI Gene 28: https://www.ncbi.nlm.nih.gov/gene/28
- Ensembl ENSG00000175164: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000175164

## Connected records

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

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