Clinicopathological analysis of homologous recombination-deficient breast cancers with special reference to response to neoadjuvant paclitaxel followed by FEC.

Approximately one-third of sporadic breast tumors show a high HRD score, indicating the presence of homologous recombination dysfunction, and they are characterized by biologically aggressive phenotypes, most commonly in the TNBC subtype, and less sensitive to P-FEC.