# H3-3B

Source: https://onco.cc/targets/h3-3b/  
OnCo record `h3-3b` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

H3-3B (Histone H3.3) is a gene. The public catalogues list it as a biomarker, and clinical evidence ties its variants to diagnosis, prognosis or drug response. Tied to Skin cancer, Melanoma and Diffuse midline glioma, H3 K27-altered.

## Summary

Variant histone H3 which replaces conventional H3 in a wide range of nucleosomes in active genes. Constitutes the predominant form of histone H3 in non-dividing cells and is incorporated into chromatin independently of DNA synthesis. Deposited at sites of nucleosomal displacement throughout transcribed genes, suggesting that it represents an epigenetic imprint of transcriptionally active chromatin.

CIViC holds 2 clinical evidence items and 1 assertion across 3 variants. Open Targets scores its association with cancer at 0.70 (direct and indirect evidence; datatypes literature 0.28, affected pathway 0.76, genetic association 0.00, somatic mutation 0.95).

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: H3.3 histone B; Histone H3.3; H3.3B; H3F3B
- Tags: cancer-genes-wave
- Symbol: H3-3B
- Class: other
- Biology: Variant histone H3 which replaces conventional H3 in a wide range of nucleosomes in active genes. Constitutes the predominant form of histone H3 in non-dividing cells and is incorporated into chromatin independently of DNA synthesis. Deposited at sites of nucleosomal displacement throughout transcribed genes, suggesting that it represents an epigenetic imprint of transcriptionally active chromatin. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling. Location: Nucleus; Chromosome (UniProt). Locus 17q25.1 (HGNC).
- Where found: Skin cancer: Open Targets association 0.55 with skin cancer (MONDO_0002898); Melanoma: Open Targets association 0.63 with melanoma (MONDO_0005105); Diffuse midline glioma, H3 K27-altered: CIViC evidence names this disease

## 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 holds 2 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.
- Diseases the sources name that have no OnCo cancer page yet, so they are not linked: Chondroblastoma.

## Sources

- HGNC HGNC:4765: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:4765
- UniProt P84243: https://www.uniprot.org/uniprotkb/P84243/entry
- NCBI Gene 3021: https://www.ncbi.nlm.nih.gov/gene/3021
- Ensembl ENSG00000132475: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000132475

## Connected records

- collections: [CIViC](https://onco.cc/collections/civic/), [Open Targets Platform](https://onco.cc/collections/open-targets/)
- cancers: [Diffuse midline glioma, H3 K27-altered (including DIPG)](https://onco.cc/cancers/dipg-dmg/), [Melanoma](https://onco.cc/cancers/melanoma/), [Skin cancer (all types)](https://onco.cc/cancers/skin-cancer/)

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JSON: https://onco.cc/api/v1/entities/h3-3b.json