# TET2

Source: https://onco.cc/targets/tet2/  
OnCo record `tet2` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

TET2 is an enzyme that helps erase methyl marks from DNA so genes can be switched back on. Losing it is one of the commonest first steps toward blood cancer; mutant IDH blocks it indirectly, which is part of how ivosidenib works when it restores normal maturation.

## Summary

TET2 (chromosome 4q24) is a dioxygenase that converts 5-methylcytosine to 5-hydroxymethylcytosine and on to 5-formylcytosine and 5-carboxylcytosine, the first steps of active DNA demethylation, and also recruits the O-GlcNAc transferase OGT to CpG-rich transcription start sites of active genes (UniProt Q6N021). The clonal-haematopoiesis pathway record lists TET2 with DNMT3A and ASXL1 among the mutations of clonal haematopoiesis of indeterminate potential, present in more than a tenth of people over 70 and progressing to myeloid neoplasm at about 0.5 to 1% a year. In OnCo it appears as the enzyme that 2-hydroxyglutarate from mutant IDH1 inhibits, so that ivosidenib restores TET2-dependent demethylation and differentiation, and as a mutation of the follicular helper T-cell lymphomas in which romidepsin is active.

## Fields

- Kind: Target
- Last checked: 2026-09-22
- Also known as: KIAA1546; tet methylcytosine dioxygenase 2
- Tags: wave5-target
- Symbol: TET2
- Class: tumor-suppressor
- Biology: Mutant IDH1 converts alpha-ketoglutarate to the oncometabolite 2-hydroxyglutarate, TET2 and histone demethylases lose activity, and blasts stop maturing; ivosidenib shuts off 2-HG production and TET2 regains activity (ivosidenib mechanism steps). TET2 itself has no drug in the corpus.
- Where found: Clonal haematopoiesis of indeterminate potential; IDH-mutant AML (TET2 inhibited by 2-hydroxyglutarate); Follicular helper T-cell lymphomas with TET2 and DNMT3A mutations

## Notes

- Prevalence not recorded in this wave: HGNC and UniProt carry no positivity rates and no other source was consulted.

## Sources

- HGNC HGNC:25941: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:25941
- UniProt Q6N021: https://www.uniprot.org/uniprotkb/Q6N021/entry
- NCBI Gene 54790: https://www.ncbi.nlm.nih.gov/gene/54790

## Connected records

- drugs: [Ivosidenib](https://onco.cc/drugs/ivosidenib/), [Romidepsin](https://onco.cc/drugs/romidepsin/)
- targets: [DNA methyltransferase 3A (DNMT3A)](https://onco.cc/targets/dnmt3a/), [IDH1 / IDH2](https://onco.cc/targets/idh/)
- cancers: [Acute myeloid leukaemia](https://onco.cc/cancers/aml/), [IDH1- and IDH2-mutated acute myeloid leukaemia](https://onco.cc/cancers/aml-idh/), [Peripheral T-cell lymphomas (including cutaneous T-cell lymphoma)](https://onco.cc/cancers/peripheral-t-cell-lymphoma/)
- technologies: [Epigenetic drugs (HDAC, DNMT, EZH2, IDH, menin, BET)](https://onco.cc/technologies/epigenetic-drugs/)
- pathways: [Clonal haematopoiesis (CHIP)](https://onco.cc/pathways/clonal-haematopoiesis/), [Epigenetic reprogramming](https://onco.cc/pathways/epigenetic-reprogramming/), [Mutant IDH / 2-hydroxyglutarate](https://onco.cc/pathways/idh-2hg/)

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JSON: https://onco.cc/api/v1/entities/tet2.json