# PREX2

Source: https://onco.cc/targets/prex2/  
OnCo record `prex2` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

PREX2 is a gene that drives cell growth when it is altered. The public catalogues list it as a drug target, an oncogene driver, a tumour suppressor and a biomarker, and clinical evidence ties its variants to diagnosis, prognosis or drug response.

## Summary

Functions as a RAC1 guanine nucleotide exchange factor (GEF), activating Rac proteins by exchanging bound GDP for free GTP. Its activity is synergistically activated by phosphatidylinositol 3,4,5-trisphosphate and the beta gamma subunits of heterotrimeric G protein. Mediates the activation of RAC1 in a PI3K-dependent manner.

CIViC holds 1 clinical evidence item and 0 assertions across 1 variant, naming Vemurafenib. Open Targets scores its association with cancer at 0.73 (direct and indirect evidence; datatypes literature 0.91, animal model 0.42, genetic association 0.45, somatic mutation 0.82). IntOGen calls it a driver in 13 cohorts (10 activating, 3 loss-of-function), covering Bladder Urothelial Carcinoma, Invasive Breast Carcinoma, Colon Adenocarcinoma, Diffuse Large B-Cell Lymphoma, NOS, Oesophageal Adenocarcinoma, Oesophageal Squamous Cell Carcinoma and others.

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: phosphatidylinositol-3,4,5-trisphosphate dependent Rac exchange factor 2; Phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 2 protein; DEP.2; FLJ12987; P-REX2; PPP1R129; DEPDC2
- Tags: cancer-genes-wave
- Symbol: PREX2
- Class: oncogene
- Biology: Functions as a RAC1 guanine nucleotide exchange factor (GEF), activating Rac proteins by exchanging bound GDP for free GTP. Its activity is synergistically activated by phosphatidylinositol 3,4,5-trisphosphate and the beta gamma subunits of heterotrimeric G protein. Mediates the activation of RAC1 in a PI3K-dependent manner. May be an important mediator of Rac signalling, acting directly downstream of both G protein-coupled receptors and phosphoinositide 3-kinase. Locus 8q13.2 (HGNC).
- Where found: Oesophageal cancer: Open Targets association 0.52 with oesophageal cancer (MONDO_0007576); IntOGen driver in 3 cohorts (ESCA, ESCC); Colorectal cancer: Open Targets association 0.55 with colorectal cancer (MONDO_0005575); IntOGen driver in 1 cohort (COAD); Gastric & gastro-oesophageal junction cancer: Open Targets association 0.51 with gastric cancer (MONDO_0001056); IntOGen driver in 1 cohort (STAD); Breast cancer: Open Targets association 0.57 with breast cancer (MONDO_0007254); IntOGen driver in 1 cohort (BRCA); Bladder & urothelial cancer: IntOGen driver in 1 cohort (BLCA); Hepatocellular carcinoma: IntOGen driver in 1 cohort (HCC)

## 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 1 therapies; IntOGen calls it an activating (Act) driver in 10 cohorts; IntOGen calls it a loss-of-function (LoF) driver in 3 cohorts; CIViC holds 1 clinical evidence items on its variants. Evidence tier "clinical-evidence" is the strongest of those signals.
- Prevalence not recorded: none of the sources gives a positivity rate.

## Sources

- HGNC HGNC:22950: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:22950
- UniProt Q70Z35: https://www.uniprot.org/uniprotkb/Q70Z35/entry
- NCBI Gene 80243: https://www.ncbi.nlm.nih.gov/gene/80243
- Ensembl ENSG00000046889: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000046889

## Connected records

- collections: [CIViC](https://onco.cc/collections/civic/), [IntOGen](https://onco.cc/collections/intogen/), [Open Targets Platform](https://onco.cc/collections/open-targets/)
- cancers: [Bladder & urothelial cancer](https://onco.cc/cancers/urothelial/), [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Colorectal cancer](https://onco.cc/cancers/colorectal/), [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/), [Hepatocellular carcinoma](https://onco.cc/cancers/hcc/), [Oesophageal cancer](https://onco.cc/cancers/esophageal/), [Ovarian cancer](https://onco.cc/cancers/ovarian/), [Pancreatic ductal adenocarcinoma](https://onco.cc/cancers/pancreatic/)

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JSON: https://onco.cc/api/v1/entities/prex2.json