# RBBP8

Source: https://onco.cc/targets/rbbp8/  
OnCo record `rbbp8` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

RBBP8 (DNA endonuclease RBBP8) is an enzyme. The public catalogues list it as a DNA repair gene, and the evidence so far is association rather than a proven role.

## Summary

Endonuclease that cooperates with the MRE11-RAD50-NBN (MRN) complex in DNA-end resection, the first step of double-strand break (DSB) repair through the homologous recombination (HR) pathway. HR is restricted to S and G2 phases of the cell cycle and preferentially repairs DSBs resulting from replication fork collapse. Key determinant of DSB repair pathway choice, as it commits cells to HR by preventing classical non-homologous end-joining (NHEJ).

Open Targets scores its association with cancer at 0.66 (direct and indirect evidence; datatypes literature 0.96, affected pathway 0.87, genetic association 0.49, somatic mutation 0.55).

## Fields

- Kind: Target
- Last checked: 2026-09-23
- Also known as: RB binding protein 8, endonuclease; DNA endonuclease RBBP8; CtIP; COM1; SCKL2
- Tags: cancer-genes-wave
- Symbol: RBBP8
- Class: enzyme
- Biology: Endonuclease that cooperates with the MRE11-RAD50-NBN (MRN) complex in DNA-end resection, the first step of double-strand break (DSB) repair through the homologous recombination (HR) pathway. HR is restricted to S and G2 phases of the cell cycle and preferentially repairs DSBs resulting from replication fork collapse. Key determinant of DSB repair pathway choice, as it commits cells to HR by preventing classical non-homologous end-joining (NHEJ). Specifically promotes the endonuclease activity of the MRN complex to clear DNA ends containing protein adducts: recruited to DSBs by NBN following phosphorylation by CDK1, and promotes the endonuclease activity of MRE11 to clear protein-DNA adducts and generate clean double-strand break ends. Functions downstream of the MRN complex and ATM, promotes ATR activation and its recruitment to DSBs in the S/G2 phase facilitating the generation of ssDNA. Component of the BRCA1-RBBP8 complex that regulates CHEK1 activation and controls cell cycle G2/M checkpoints on DNA damage. Location: Nucleus; Chromosome (UniProt). Locus 18q11.2 (HGNC).

## 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: UniProt keyword "DNA repair". Evidence tier "association-only" is the strongest of those signals.
- Prevalence not recorded: none of the sources gives a positivity rate.

## Sources

- HGNC HGNC:9891: https://www.genenames.org/data/gene-symbol-report/#!/hgnc_id/HGNC:9891
- UniProt Q99708: https://www.uniprot.org/uniprotkb/Q99708/entry
- NCBI Gene 5932: https://www.ncbi.nlm.nih.gov/gene/5932
- Ensembl ENSG00000101773: https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000101773

## Connected records

- collections: [Open Targets Platform](https://onco.cc/collections/open-targets/)

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JSON: https://onco.cc/api/v1/entities/rbbp8.json