Age

18–70

Sex

FEMALE

Healthy volunteers

Not accepted

1. Female patients aged 18-70 years with pathologically confirmed HER2-low breast cancer (defined as IHC 2+/ISH- or IHC 1+ per ASCO/CAP guidelines);
2. ECOG performance status of 0 or 1;
3. Treatment-naïve operable primary breast cancer with completed homologous recombination deficiency (HRD) assessment;
5）Absence of distant metastasis; 6）Availability of adequate tumor tissue and blood samples for biomarker analysis.

Distribution of the Homologous Recombination-related (HRR) Genesmutationsand HRD in Breast Cancer