Objective:

To assess the relationship between homologous recombination deficiency (HRD) and breast cancer risk categories determined by a 70-gene assay.

Key Findings:

• HRD is highest in patients with a high risk 2 score.
• Basal-like high risk 2 subtype shows the highest association with HRD.
• Luminal high risk 2 subtype has increased HRD compared to luminal high risk 1, but lower than basal group.
• High scores correlate with benefit from anthracyclines.

Interpretation:

The correlation between higher HRD and treatment response may explain the preferential effectiveness of anthracyclines in high score patients.

Limitations:

Conclusion:

The findings suggest a potential link between HRD and treatment outcomes in breast cancer, particularly regarding anthracycline efficacy.