# Tumour (somatic or germline) BRCA1/2 mutation and HRR gene alterations

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

## TL;DR

Tumour BRCA testing finds BRCA1/2 mutations in the cancer itself, whether inherited or acquired; wider panels add other repair genes such as ATM and PALB2. Ovarian and prostate cancer labels accept the tumour result for PARP inhibitors.

## Summary

Sequencing tumour tissue or plasma DNA detects BRCA1/2 mutations regardless of origin (about a third of ovarian tumour BRCA mutations are somatic only) and, on larger panels, alterations in the homologous recombination repair genes. Olaparib is labelled for germline or somatic BRCA-mutated ovarian cancer (first-line and recurrent maintenance), for HRR gene-mutated metastatic castration-resistant prostate cancer after enzalutamide or abiraterone (PROfound; genes listed on the FoundationOne CDx claim), and with abiraterone for BRCA-mutated mCRPC; rucaparib for BRCA-mutated ovarian cancer and mCRPC from plasma; talazoparib with enzalutamide for HRR gene-mutated mCRPC, the label listing ATM, ATR, BRCA1, BRCA2, CDK12, CHEK2, FANCA, MLH1, MRE11A, NBN, PALB2 and RAD51C. FoundationOne CDx and Liquid CDx, FoundationFocus CDxBRCA and myChoice CDx carry the tumour claims.

## Fields

- Kind: Biomarker
- Last checked: 2026-09-23
- Also known as: somatic BRCA; sBRCA; tumor BRCA; tBRCA; BRCAm; BRCA-mutated; HRR gene mutation; HRRm; homologous recombination repair gene alteration; ATM mutation; PALB2 mutation
- Tags: biomarker; brca

## Sources

- Lynparza prescribing information (DailyMed): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=741ff3e3-dc1a-45a6-84e5-2481b27131aa
- Rubraca prescribing information (DailyMed): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0295d202-1cfe-7659-e063-6294a90a476e
- Talzenna prescribing information (DailyMed): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=13839d4f-6acf-4ffb-a128-79df59319273

## Connected records

- biomarkers: [Folate receptor alpha expression (FRα-positive, PS2+ >= 75%)](https://onco.cc/biomarkers/folr1-expression/), [Germline BRCA1/2 pathogenic variant (gBRCAm)](https://onco.cc/biomarkers/brca-germline/), [HRD-positive (genomic instability score)](https://onco.cc/biomarkers/hrd-positive/)
- cancers: [High-grade serous ovarian cancer](https://onco.cc/cancers/high-grade-serous-ovarian-cancer/), [Metastatic castration-resistant prostate cancer](https://onco.cc/cancers/prostate-mcrpc/), [Ovarian cancer](https://onco.cc/cancers/ovarian/), [Platinum-sensitive ovarian cancer](https://onco.cc/cancers/platinum-sensitive-ovarian-cancer/)
- drugs: [FoundationOne CDx / Liquid CDx](https://onco.cc/drugs/foundationone-cdx/), [myChoice CDx](https://onco.cc/drugs/mychoice-cdx/), [Niraparib](https://onco.cc/drugs/niraparib/), [Olaparib](https://onco.cc/drugs/olaparib/), [Rucaparib](https://onco.cc/drugs/rucaparib/), [Talazoparib](https://onco.cc/drugs/talazoparib/)
- terms: [BRCA reversion mutations](https://onco.cc/terms/brca-reversion-mutations/), [Germline vs somatic mutations](https://onco.cc/terms/germline-vs-somatic/), [Homologous recombination deficiency (HRD)](https://onco.cc/terms/hrd/), [Next-generation sequencing (NGS)](https://onco.cc/terms/ngs/)
- targets: [BRCA1 / BRCA2 (HRD)](https://onco.cc/targets/brca/)

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JSON: https://onco.cc/api/v1/entities/brca-somatic.json