# MED12

Source: https://onco.cc/targets/med12/  
OnCo record `med12` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

MED12 (Mediator of RNA polymerase II transcription subunit 12) 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 Prostate cancer, Cervical cancer, Endometrial cancer and 5 more.

## Summary

Component of the Mediator complex, a coactivator involved in the regulated transcription of nearly all RNA polymerase II-dependent genes. Mediator functions as a bridge to convey information from gene-specific regulatory proteins to the basal RNA polymerase II transcription machinery. Mediator is recruited to promoters by direct interactions with regulatory proteins and serves as a scaffold for the assembly of a functional pre-initiation complex with RNA polymerase II and the general transcription factors.

Open Targets scores its association with cancer at 0.69 (direct and indirect evidence; datatypes literature 0.97, affected pathway 0.38, genetic association 0.19, somatic mutation 0.80). IntOGen calls it a driver in 14 cohorts (9 activating, 5 loss-of-function), covering Acute Lymphoblastic Leukaemia, Cervical Squamous Cell Carcinoma, Chronic Lymphocytic Leukaemia/Small Lymphocytic Lymphoma, Glioblastoma Multiforme, Low-Grade Glioma, NOS, Neuroblastoma and others.

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: mediator complex subunit 12; Mediator of RNA polymerase II transcription subunit 12; CAGH45; OPA1; TRAP230; KIAA0192; ARC240; Kto; TNRC11; FGS1
- Tags: cancer-genes-wave
- Symbol: MED12
- Class: transcription
- Biology: Component of the Mediator complex, a coactivator involved in the regulated transcription of nearly all RNA polymerase II-dependent genes. Mediator functions as a bridge to convey information from gene-specific regulatory proteins to the basal RNA polymerase II transcription machinery. Mediator is recruited to promoters by direct interactions with regulatory proteins and serves as a scaffold for the assembly of a functional pre-initiation complex with RNA polymerase II and the general transcription factors. This subunit may specifically regulate transcription of targets of the Wnt signalling pathway and SHH signalling pathway. Location: Nucleus (UniProt). Locus Xq13.1 (HGNC).
- Where found: Prostate cancer: IntOGen driver in 5 cohorts (PRAD, PROSTATE); Cervical cancer: IntOGen driver in 2 cohorts (CESC); Endometrial cancer: IntOGen driver in 1 cohort (UCEC); Skin cancer: Open Targets association 0.52 with skin cancer (MONDO_0002898); Leukaemia: Open Targets association 0.51 with leukaemia (MONDO_0005059); Chronic lymphocytic leukaemia: IntOGen driver in 2 cohorts (CLLSLL)

## 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 9 cohorts; IntOGen calls it a loss-of-function (LoF) driver in 5 cohorts. Evidence tier "cohort-driver" is the strongest of those signals.
- Prevalence not recorded: none of the sources gives a positivity rate.
- Diseases the sources name that have no OnCo cancer page yet, so they are not linked: Low-Grade Glioma, NOS.

## Sources

- HGNC HGNC:11957: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:11957
- UniProt Q93074: https://www.uniprot.org/uniprotkb/Q93074/entry
- NCBI Gene 9968: https://www.ncbi.nlm.nih.gov/gene/9968
- Ensembl ENSG00000184634: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000184634

## 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/), [Cervical cancer](https://onco.cc/cancers/cervical/), [Chronic lymphocytic leukaemia](https://onco.cc/cancers/cll/), [Endometrial cancer](https://onco.cc/cancers/endometrial/), [Glioma & glioblastoma](https://onco.cc/cancers/glioblastoma/), [Leukaemia (all types)](https://onco.cc/cancers/leukaemia/), [Prostate cancer](https://onco.cc/cancers/prostate/), [Skin cancer (all types)](https://onco.cc/cancers/skin-cancer/)

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JSON: https://onco.cc/api/v1/entities/med12.json