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Updated: Oct 23, 2025
Identifying the Effects of BRCA1 Mutations on Homologous Recombination using Cells that Express Endogenous Wild-type BRCA1
Published on: February 17, 2011
Utility of Homologous Recombination Deficiency Biomarkers Across Cancer Types
Shiro Takamatsu1, J B Brown2,3, Ken Yamaguchi1
1Department of Gynecology and Obstetrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Abstract:
Homologous recombination DNA repair deficiency (HRD) is associated with sensitivity to platinum and poly (ADP-ribose) polymerase inhibitors in certain cancer types, including breast, ovarian, pancreatic, and prostate. In these cancers, BRCA1/2 alterations and genomic scar signatures are useful indicators for assessing HRD. However, alterations in other homologous recombination repair (HRR)-related genes and their clinical significance in other cancer types have not been adequately and systematically investigated.
Methods:
We obtained data sets of all solid tumors in The Cancer Genome Atlas and Cancer Cell Line Encyclopedia, and comprehensively analyzed HRR pathway gene alterations, their loss-of-heterozygosity status, and per-sample genomic scar scores, that is, the HRD score and mutational signature 3 ratio, DNA methylation profiles, gene expression profiles, somatic TP53 mutations, sex, and clinical or in vitro response to chemical exposure.
Results:
Biallelic alterations in HRR genes other than BRCA1/2 were also associated with elevated genomic scar scores. The association between HRR-related gene alterations and genomic scar scores differed significantly by sex and the presence of somatic TP53 mutations. HRD tumors determined by a combination of indices also showed HRD features in gene expression analysis and exhibited significantly higher sensitivity to DNA-damaging agents than non-HRD cases in both clinical samples and cell lines.
Conclusion:
This study provides evidence for the usefulness of HRD analysis in all cancer types, improves chemotherapy decision making and its efficacy in clinical settings, and represents a substantial advancement in precision oncology.A comprehensive pan-cancer analysis on the clinical significance of homologous recombination deficiency.
Insights
Homologous recombination deficiency (HRD) is linked to DNA repair and impacts chemotherapy sensitivity across various cancers. This study expands HRD analysis to all tumor types, improving treatment decisions for precision oncology.
Area of Science:
- Genomic instability and DNA repair mechanisms in oncology.
- Pan-cancer genomic analysis and biomarker discovery.
Background:
- Homologous recombination DNA repair deficiency (HRD) predicts sensitivity to platinum-based chemotherapy and PARP inhibitors in specific cancers like breast and ovarian.
- BRCA1/2 alterations and genomic scars are established HRD biomarkers, but the role of other HRR genes across all cancer types remains under-investigated.
Purpose of the Study:
- To comprehensively analyze homologous recombination repair (HRR) pathway gene alterations and their clinical significance across all solid tumor types.
- To investigate the association between HRR gene alterations, genomic scar scores (HRD score, mutational signature 3 ratio), and sensitivity to DNA-damaging agents.
- To evaluate the utility of pan-cancer HRD analysis for improving chemotherapy decision-making in precision oncology.
Main Methods:
- Utilized The Cancer Genome Atlas and Cancer Cell Line Encyclopedia datasets for comprehensive analysis of solid tumors.
- Assessed HRR pathway gene alterations, loss-of-heterozygosity, HRD scores, mutational signatures, DNA methylation, gene expression, TP53 mutations, and clinical/in vitro drug response.
- Investigated the influence of sex and TP53 mutation status on the relationship between HRR alterations and genomic scars.
Main Results:
- Biallelic alterations in non-BRCA1/2 HRR genes correlated with elevated genomic scar scores.
- The association between HRR alterations and genomic scars varied significantly by sex and TP53 mutation status.
- HRD-determined tumors exhibited distinct gene expression profiles and significantly higher sensitivity to DNA-damaging agents compared to non-HRD tumors.
Conclusions:
- HRD analysis is valuable across all cancer types, offering improved chemotherapy decision-making and efficacy.
- This pan-cancer approach represents a significant advancement in precision oncology by broadening the application of HRD biomarkers.
- The findings support the expanded use of HRD assessment for personalized cancer treatment strategies.
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