# A RAD51 assay feasible in routine tumor samples calls PARP inhibitor response beyond BRCA mutation

Source: https://onco.cc/key-papers/paper-castroviejo-bermejo-embo-mol-med/  
OnCo record `paper-castroviejo-bermejo-embo-mol-med` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Paper cited by one technology page, indexed on Europe PMC as PubMed record 30377213 and published in EMBO molecular medicine; the citing page links this DOI, which is how the record was matched.

## Summary

Poly(ADP-ribose) polymerase (PARP) inhibitors (PARPi) are effective in cancers with defective homologous recombination DNA repair (HRR), including BRCA1/2-related cancers. A test to identify additional HRR-deficient tumors will help to extend their use in new indications. We evaluated the activity of the PARPi olaparib in patient-derived tumor xenografts (PDXs) from breast cancer (BC) patients and investigated mechanisms of sensitivity through exome sequencing, BRCA1 promoter methylation analysis, and immunostaining of HRR proteins, including RAD51 nuclear foci. In an independent BC PDX panel, the predictive capacity of the RAD51 score and the homologous recombination deficiency (HRD) score were compared. To examine the clinical feasibility of the RAD51 assay, we scored archival breast tumor samples, including PALB2-related hereditary cancers. The RAD51 score was highly discriminative of PARPi sensitivity versus PARPi resistance in BC PDXs and outperformed the genomic test. In clinical samples, all PALB2-related tumors were classified as HRR-deficient by the RAD51 score. The functional biomarker RAD51 enables the identification of PARPi-sensitive BC and broadens the population who may benefit from this therapy beyond BRCA1/2-related cancers.

Indexed on Europe PMC as PubMed record 30377213 (DOI 10.15252/emmm.201809172). Matched by DOI alone: one technology page cites this DOI among its external links (the pages are listed under Related), and this page was written so that the citation resolves inside OnCo. No figure has been checked by an editor.

## Fields

- Kind: Key paper
- Last checked: 2026-09-22
- Tags: europepmc-ingest
- Journal: EMBO molecular medicine
- Year: 2018
- DOI: 10.15252/emmm.201809172
- Authors: Castroviejo-Bermejo M, Cruz C, Llop-Guevara A, et al.
- What it means: One technology page on OnCo cites this paper by its DOI; this record gives the citation a page of its own so a reader can follow it without leaving OnCo. Read the abstract above alongside the citing page listed under Related; the record was created automatically from the Europe PMC entry and its figures have not been checked by hand.
- Caveats: Matched to the citing OnCo records by DOI alone; the summary reproduces the Europe PMC abstract and no figure has been verified against the full paper.

## Sources

- EMBO Mol Med 2018: https://doi.org/10.15252/emmm.201809172
- PubMed: https://pubmed.ncbi.nlm.nih.gov/30377213/
- Europe PMC: https://europepmc.org/article/MED/30377213

## Connected records

- technologies: [RAD51 foci assay (functional HRD test)](https://onco.cc/technologies/rad51-foci-assay/)

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