# NBN

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

## TL;DR

NBN (Nibrin) is a gene. The public catalogues list it as a drug target, a biomarker and a DNA repair gene, and clinical evidence ties its variants to diagnosis, prognosis or drug response. Tied to Non-Hodgkin lymphoma, Leukaemia, Breast cancer and 5 more.

## Summary

Component of the MRN complex, which plays a central role in double-strand break (DSB) repair, DNA recombination, maintenance of telomere integrity and meiosis. The MRN complex is involved in the repair of DNA double-strand breaks (DSBs) via homologous recombination (HR), an error-free mechanism which primarily occurs during S and G2 phases. The complex (1) mediates the end resection of damaged DNA, which generates proper single-stranded DNA, a key initial steps in HR, and is (2) required for the recruitment of other repair factors and efficient activation of ATM and ATR upon DNA damage.

CIViC holds 2 clinical evidence items and 0 assertions across 2 variants, naming Olaparib and GPI-15427. Open Targets scores its association with cancer at 0.85 (direct and indirect evidence; datatypes genetic literature 0.76, affected pathway 0.87, literature 0.95, genetic association 0.78, somatic mutation 0.83, animal model 0.50).

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: nibrin; Nibrin; AT-V2; AT-V1; NBS1
- Tags: cancer-genes-wave
- Symbol: NBN
- Class: other
- Biology: Component of the MRN complex, which plays a central role in double-strand break (DSB) repair, DNA recombination, maintenance of telomere integrity and meiosis. The MRN complex is involved in the repair of DNA double-strand breaks (DSBs) via homologous recombination (HR), an error-free mechanism which primarily occurs during S and G2 phases. The complex (1) mediates the end resection of damaged DNA, which generates proper single-stranded DNA, a key initial steps in HR, and is (2) required for the recruitment of other repair factors and efficient activation of ATM and ATR upon DNA damage. The MRN complex possesses single-strand endonuclease activity and double-strand-specific 3'-5' exonuclease activity, which are provided by MRE11, to initiate end resection, which is required for single-strand invasion and recombination. Within the MRN complex, NBN acts as a protein-protein adapter, which specifically recognises and binds phosphorylated proteins, promoting their recruitment to DNA damage sites. Recruits MRE11 and RAD50 components of the MRN complex to DSBs in response to DNA damage. Location: Nucleus; Chromosome; Nucleus, PML body; Chromosome, telomere (UniProt). Locus 8q21.3 (HGNC).
- Where found: Non-Hodgkin lymphoma: Open Targets association 0.76 with non-Hodgkin lymphoma (MONDO_0018908); Leukaemia: Open Targets association 0.72 with leukaemia (MONDO_0005059); Breast cancer: Open Targets association 0.72 with breast cancer (MONDO_0007254); Ovarian cancer: Open Targets association 0.67 with ovarian cancer (MONDO_0008170); CIViC evidence names this disease; Gastric & gastro-oesophageal junction cancer: Open Targets association 0.65 with gastric cancer (MONDO_0001056); Head and neck squamous cell carcinoma: 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 lists 2 therapies; CIViC holds 2 clinical evidence items on its variants; UniProt keyword "DNA repair". Evidence tier "clinical-evidence" is the strongest of those signals.
- Prevalence not recorded: none of the sources gives a positivity rate.

## Sources

- HGNC HGNC:7652: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:7652
- UniProt O60934: https://www.uniprot.org/uniprotkb/O60934/entry
- NCBI Gene 4683: https://www.ncbi.nlm.nih.gov/gene/4683
- Ensembl ENSG00000104320: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000104320

## Connected records

- collections: [CIViC](https://onco.cc/collections/civic/), [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/), [Head and neck squamous cell carcinoma](https://onco.cc/cancers/head-and-neck/), [Leukaemia (all types)](https://onco.cc/cancers/leukaemia/), [Non-Hodgkin lymphoma (all types)](https://onco.cc/cancers/non-hodgkin-lymphoma/), [Ovarian cancer](https://onco.cc/cancers/ovarian/), [Prostate cancer](https://onco.cc/cancers/prostate/), [Sarcomas (soft tissue, bone, GIST)](https://onco.cc/cancers/sarcoma/)

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