# AFF1

Source: https://onco.cc/targets/aff1/  
OnCo record `aff1` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

AFF1 (AF4/FMR2 family member 1) is a gene whose normal job is to hold cell growth in check. The public catalogues list it as a tumour suppressor and a fusion partner, and it is called a cancer driver by mutation analysis of patient cohorts. Tied to Leukaemia, Non-Hodgkin lymphoma, Melanoma and 1 more.

## Summary

Plays an essential role in the activation of transcription elongation from RNA polymerase II promoters, after transcriptional pausing in response to DNA damage. Upon DNA damage, AFF1-mediated transcriptional recovery requires AFF1 poly-ADP-ribosylation by PARP1.

Open Targets scores its association with cancer at 0.45 (direct and indirect evidence; datatypes literature 0.58, animal model 0.39, genetic association 0.03, somatic mutation 0.70). IntOGen calls it a driver in 1 cohort (0 activating, 1 loss-of-function), covering Melanoma.

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: ALF transcription elongation factor 1; AF4/FMR2 family member 1; AF-4; AF4; PBM1; MLLT2
- Tags: cancer-genes-wave
- Symbol: AFF1
- Class: tumor-suppressor
- Biology: Plays an essential role in the activation of transcription elongation from RNA polymerase II promoters, after transcriptional pausing in response to DNA damage. Upon DNA damage, AFF1-mediated transcriptional recovery requires AFF1 poly-ADP-ribosylation by PARP1. Location: Nucleus (UniProt). Locus 4q21.3-q22.1 (HGNC).
- Where found: Leukaemia: Open Targets association 0.57 with leukaemia (MONDO_0005059); Non-Hodgkin lymphoma: Open Targets association 0.55 with non-Hodgkin lymphoma (MONDO_0018908); Melanoma: IntOGen driver in 1 cohort (MEL); Acute lymphoblastic leukaemia: Open Targets association 0.54 with acute lymphoblastic leukaemia (MONDO_0004967)

## 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 a loss-of-function (LoF) driver in 1 cohort; UniProt disease notes describe a translocation or gene fusion involving the gene. Evidence tier "cohort-driver" is the strongest of those signals.
- Prevalence not recorded: none of the sources gives a positivity rate.

## Sources

- HGNC HGNC:7135: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:7135
- UniProt P51825: https://www.uniprot.org/uniprotkb/P51825/entry
- NCBI Gene 4299: https://www.ncbi.nlm.nih.gov/gene/4299
- Ensembl ENSG00000172493: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000172493

## Connected records

- collections: [IntOGen](https://onco.cc/collections/intogen/), [Open Targets Platform](https://onco.cc/collections/open-targets/)
- cancers: [Acute lymphoblastic leukaemia](https://onco.cc/cancers/all-leukemia/), [Leukaemia (all types)](https://onco.cc/cancers/leukaemia/), [Melanoma](https://onco.cc/cancers/melanoma/), [Non-Hodgkin lymphoma (all types)](https://onco.cc/cancers/non-hodgkin-lymphoma/)

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JSON: https://onco.cc/api/v1/entities/aff1.json