# EXT2

Source: https://onco.cc/targets/ext2/  
OnCo record `ext2` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

EXT2 (Exostosin-2) is an enzyme. In the public catalogues the evidence so far is association rather than a proven role. Tied to Ovarian cancer, Skin cancer and Breast cancer.

## Summary

Glycosyltransferase forming with EXT1 the heterodimeric heparan sulfate polymerase which catalyses the elongation of the heparan sulfate glycan backbone. Glycan backbone extension consists in the alternating transfer of (1->4)-beta-D-GlcA and (1->4)-alpha-D-GlcNAc residues from their respective UDP-sugar donors. Both EXT1 and EXT2 are required for the full activity of the polymerase since EXT1 bears the N-acetylglucosaminyl-proteoglycan 4-beta-glucuronosyltransferase activity within the complex while EXT2 carries the glucuronosyl-N-acetylglucosaminyl-proteoglycan 4-alpha-N-acetylglucosaminyltransferase activity.

Open Targets scores its association with cancer at 0.72 (direct and indirect evidence; datatypes literature 0.84, affected pathway 0.25, genetic association 0.64, somatic mutation 0.98).

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: exostosin glycosyltransferase 2; Exostosin-2
- Tags: cancer-genes-wave
- Symbol: EXT2
- Class: enzyme
- Biology: Glycosyltransferase forming with EXT1 the heterodimeric heparan sulfate polymerase which catalyses the elongation of the heparan sulfate glycan backbone. Glycan backbone extension consists in the alternating transfer of (1->4)-beta-D-GlcA and (1->4)-alpha-D-GlcNAc residues from their respective UDP-sugar donors. Both EXT1 and EXT2 are required for the full activity of the polymerase since EXT1 bears the N-acetylglucosaminyl-proteoglycan 4-beta-glucuronosyltransferase activity within the complex while EXT2 carries the glucuronosyl-N-acetylglucosaminyl-proteoglycan 4-alpha-N-acetylglucosaminyltransferase activity. Heparan sulfate proteoglycans are ubiquitous components of the extracellular matrix and play an important role in tissue homeostasis and signalling. Location: Golgi apparatus membrane; Golgi apparatus, cis-Golgi network membrane; Endoplasmic reticulum membrane; Secreted (UniProt). Locus 11p11.2 (HGNC).
- Where found: Ovarian cancer: Open Targets association 0.57 with ovarian cancer (MONDO_0008170); Skin cancer: Open Targets association 0.51 with skin cancer (MONDO_0002898); Breast cancer: Open Targets association 0.50 with breast cancer (MONDO_0007254)

## 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:3513: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:3513
- UniProt Q93063: https://www.uniprot.org/uniprotkb/Q93063/entry
- NCBI Gene 2132: https://www.ncbi.nlm.nih.gov/gene/2132
- Ensembl ENSG00000151348: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000151348

## Connected records

- collections: [Open Targets Platform](https://onco.cc/collections/open-targets/)
- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Ovarian cancer](https://onco.cc/cancers/ovarian/), [Skin cancer (all types)](https://onco.cc/cancers/skin-cancer/)

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JSON: https://onco.cc/api/v1/entities/ext2.json