{"entity":{"id":"hrd-testing","kind":"technology","name":"HRD & BRCA testing","aka":[],"tldr":"Tests that reveal whether a tumour has a broken DNA repair system, which predicts response to PARP inhibitors and platinum.","summary":"HRD and BRCA testing identifies tumours whose homologous recombination DNA repair is defective and therefore vulnerable to PARP inhibitors and platinum. It combines germline and somatic BRCA1/2 sequencing with genomic-scar scores such as the myChoice CDx genomic instability score and FoundationOne LOH, which sum loss of heterozygosity, telomeric allelic imbalance and large-scale transitions into one measure. This extends PARP-inhibitor benefit beyond BRCA carriers. The scar, however, is permanent: it persists even after reversion mutations restore repair and resistance emerges, and the thresholds defining HRD-positive are still debated. Functional assays such as RAD51 foci and mutational signature 3 are emerging alternatives that may capture current repair status. These tests reveal whether a tumour's DNA repair is broken, which predicts response to PARP inhibitors and platinum.","status":"standard-of-care","asOf":"2026-09-04","links":[{"label":"PAOLA-1: olaparib added to bevacizumab maintenance in newly diagnosed ovarian cancer, with benefit confined to HRD-positive tumours (New England Journal of Medicine 2019)","url":"https://doi.org/10.1056/NEJMoa1911361"}],"tags":[],"related":["hrd-genomic-scar-scores","rad51-foci-assay","stride-dna-break-detection"],"cancers":[],"sections":["diagnostics"],"technologies":[],"targets":["brca","parp"],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["hrd"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"principle":"Loss of heterozygosity, telomeric allelic imbalance, and large-scale transitions summed into a genomic instability score.","strengths":["Extends PARP-inhibitor benefit beyond BRCA carriers"],"limitations":["Scar is permanent even after resistance emerges","Threshold debates"]},"route":"/technologies/hrd-testing/","neighbours":{"technology":[{"id":"hrd-genomic-scar-scores","kind":"technology","name":"HRD genomic scar scores (GIS, LOH, HRDetect)","route":"/technologies/hrd-genomic-scar-scores/"},{"id":"rad51-foci-assay","kind":"technology","name":"RAD51 foci assay (functional HRD test)","route":"/technologies/rad51-foci-assay/"},{"id":"stride-dna-break-detection","kind":"technology","name":"STRIDE DNA break detection (intoDNA)","route":"/technologies/stride-dna-break-detection/"}],"section":[{"id":"diagnostics","kind":"section","name":"Diagnostics & Biomarkers","route":"/fronts/diagnostics/"}],"target":[{"id":"brca","kind":"target","name":"BRCA1 / BRCA2 (HRD)","route":"/targets/brca/"},{"id":"parp","kind":"target","name":"PARP","route":"/targets/parp/"}],"term":[{"id":"genome-instability-mutation","kind":"term","name":"Enabling characteristic: genome instability and mutation","route":"/terms/genome-instability-mutation/"},{"id":"hrd","kind":"term","name":"Homologous recombination deficiency (HRD)","route":"/terms/hrd/"},{"id":"hrd-in-breast-cancer","kind":"term","name":"Homologous recombination deficiency (HRD) in breast cancer","route":"/terms/hrd-in-breast-cancer/"}],"cancer":[{"id":"ovarian","kind":"cancer","name":"Ovarian cancer","route":"/cancers/ovarian/"},{"id":"pancreatic","kind":"cancer","name":"Pancreatic ductal adenocarcinoma","route":"/cancers/pancreatic/"},{"id":"platinum-sensitive-ovarian-cancer","kind":"cancer","name":"Platinum-sensitive ovarian cancer","route":"/cancers/platinum-sensitive-ovarian-cancer/"},{"id":"tnbc","kind":"cancer","name":"Triple-negative breast cancer (TNBC)","route":"/cancers/tnbc/"}],"paper":[{"id":"paper-park-hrd-pancreatic-platinum-ccr-2020","kind":"paper","name":"Genomic methods identify homologous recombination deficiency in pancreas adenocarcinoma and optimize treatment selection","route":"/key-papers/paper-park-hrd-pancreatic-platinum-ccr-2020/"},{"id":"paper-telli-hrd-score-platinum-tnbc-ccr-2016","kind":"paper","name":"Homologous recombination deficiency (HRD) score predicts response to platinum-containing neoadjuvant chemotherapy in patients with triple-negative breast cancer","route":"/key-papers/paper-telli-hrd-score-platinum-tnbc-ccr-2016/"},{"id":"paper-davies-nat-med","kind":"paper","name":"HRDetect is a predictor of BRCA1 and BRCA2 deficiency based on mutational signatures","route":"/key-papers/paper-davies-nat-med/"},{"id":"paper-paola-1-nejm-2019","kind":"paper","name":"PAOLA-1: olaparib added to bevacizumab maintenance in newly diagnosed ovarian cancer, with benefit confined to HRD-positive tumours","route":"/key-papers/paper-paola-1-nejm-2019/"},{"id":"paper-loibl-geparsixto-survival-hrd-ann-oncol-2018","kind":"paper","name":"Survival analysis of carboplatin added to an anthracycline/taxane-based neoadjuvant chemotherapy and HRD score as predictor of response-final results from GeparSixto","route":"/key-papers/paper-loibl-geparsixto-survival-hrd-ann-oncol-2018/"},{"id":"paper-waddell-whole-genomes-pancreatic-nature-2015","kind":"paper","name":"Whole genomes redefine the mutational landscape of pancreatic cancer","route":"/key-papers/paper-waddell-whole-genomes-pancreatic-nature-2015/"},{"id":"paper-staaf-tnbc-whole-genome-scan-b-nat-med-2019","kind":"paper","name":"Whole-genome sequencing of triple-negative breast cancers in a population-based clinical study","route":"/key-papers/paper-staaf-tnbc-whole-genome-scan-b-nat-med-2019/"}],"pathway":[{"id":"ddr","kind":"pathway","name":"DNA damage response & homologous recombination","route":"/pathways/ddr/"},{"id":"homologous-recombination-repair","kind":"pathway","name":"Double-strand break repair: HR versus end joining","route":"/pathways/homologous-recombination-repair/"},{"id":"mutagenesis-signatures","kind":"pathway","name":"Mutagenesis & mutational signatures","route":"/pathways/mutagenesis-signatures/"},{"id":"synthetic-lethality-map","kind":"pathway","name":"Synthetic lethality: paired dependencies","route":"/pathways/synthetic-lethality-map/"}],"person":[{"id":"isabelle-ray-coquard","kind":"person","name":"Isabelle Ray-Coquard","route":"/people/isabelle-ray-coquard/"},{"id":"mary-claire-king","kind":"person","name":"Mary-Claire King","route":"/people/mary-claire-king/"},{"id":"serena-nik-zainal","kind":"person","name":"Serena Nik-Zainal","route":"/people/serena-nik-zainal/"}],"bottleneck":[{"id":"b-biomarker-validation","kind":"bottleneck","name":"Biomarkers are not validated or standardised","route":"/bottlenecks/b-biomarker-validation/"}],"idea":[{"id":"idea-tr2-hrd-functional-standard","kind":"idea","name":"A functional test for homologous recombination deficiency validated across laboratories","route":"/ideas/idea-tr2-hrd-functional-standard/"}],"institution":[{"id":"sgo","kind":"institution","name":"Society of Gynecologic Oncology","route":"/institutions/sgo/"}],"drug":[{"id":"bracanalysis-cdx","kind":"drug","name":"BRACAnalysis CDx","route":"/drugs/bracanalysis-cdx/"},{"id":"mychoice-cdx","kind":"drug","name":"myChoice CDx","route":"/drugs/mychoice-cdx/"}],"company":[{"id":"arcagy-gineco","kind":"company","name":"ARCAGY-GINECO","route":"/companies/arcagy-gineco/"},{"id":"intodna","kind":"company","name":"intoDNA","route":"/companies/intodna/"},{"id":"myriad-genetics","kind":"company","name":"Myriad Genetics","route":"/companies/myriad-genetics/"}],"roadmap":[{"id":"diagnostics-roadmap","kind":"roadmap","name":"Diagnostics roadmap: stains → gene panels → blood tests that decide treatment","route":"/roadmaps/diagnostics-roadmap/"}]}}