# AFF3

Source: https://onco.cc/targets/aff3/  
OnCo record `aff3` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

AFF3 (AF4/FMR2 family member 3) is a protein that switches other genes on and off. The public catalogues list it as an oncogene driver and a tumour suppressor, and it is called a cancer driver by mutation analysis of patient cohorts. Tied to Breast cancer, Thyroid cancer, Skin cancer and 4 more.

## Summary

Putative transcription activator that may function in lymphoid development and oncogenesis. Binds, in vitro, to double-stranded DNA.

Open Targets scores its association with cancer at 0.65 (direct and indirect evidence; datatypes literature 0.87, animal model 0.46, genetic association 0.00, somatic mutation 0.84). IntOGen calls it a driver in 2 cohorts (1 activating, 1 loss-of-function), covering Lung Adenocarcinoma, Well-Differentiated Thyroid Cancer.

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: ALF transcription elongation factor 3; AF4/FMR2 family member 3; MLLT2-like; LAF4
- Tags: cancer-genes-wave
- Symbol: AFF3
- Class: transcription
- Biology: Putative transcription activator that may function in lymphoid development and oncogenesis. Binds, in vitro, to double-stranded DNA. Location: Nucleus (UniProt). Locus 2q11.2 (HGNC).
- Where found: Breast cancer: Open Targets association 0.58 with breast cancer (MONDO_0007254); Thyroid cancer: IntOGen driver in 1 cohort (WDTC); Skin cancer: Open Targets association 0.55 with skin cancer (MONDO_0002898); Lung cancer: Open Targets association 0.55 with lung cancer (MONDO_0008903); Gastric & gastro-oesophageal junction cancer: Open Targets association 0.52 with gastric cancer (MONDO_0001056); Non-small-cell lung cancer: IntOGen driver in 1 cohort (LUAD)

## 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: IntOGen calls it an activating (Act) driver in 1 cohort; IntOGen calls it a loss-of-function (LoF) driver in 1 cohort. Evidence tier "cohort-driver" is the strongest of those signals.
- Prevalence not recorded: none of the sources gives a positivity rate.

## Sources

- HGNC HGNC:6473: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:6473
- UniProt P51826: https://www.uniprot.org/uniprotkb/P51826/entry
- NCBI Gene 3899: https://www.ncbi.nlm.nih.gov/gene/3899
- Ensembl ENSG00000144218: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000144218

## Connected records

- collections: [IntOGen](https://onco.cc/collections/intogen/), [Open Targets Platform](https://onco.cc/collections/open-targets/)
- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/), [Lung cancer (all types)](https://onco.cc/cancers/lung-cancer/), [Non-small-cell lung cancer](https://onco.cc/cancers/nsclc/), [Papillary thyroid cancer](https://onco.cc/cancers/papillary-thyroid-cancer/), [Skin cancer (all types)](https://onco.cc/cancers/skin-cancer/), [Thyroid cancer](https://onco.cc/cancers/thyroid/)

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JSON: https://onco.cc/api/v1/entities/aff3.json