BRCAness and prognosis of triple-negative breast cancer patients treated with neoadjuvant chemotherapy.

e12111Background: Triple-negative breast cancers (TNBCs) consist of patients which are recalcitrant to chemotherapy. Dysfunction of BRCA, called “BRCAness” may be predictive of sensitivity to DNA repair inhibitors. However, adequate assay of “BRCAness” are still not confirmed. Multiplex ligation-dependent probe amplification (MLPA) with the Probemix P376-B2 BRCA1ness (MRC-Holland, The Netherlands) can be one method to determine BRCAness. We previously reported that “BRCAness” by MLPA predict resistance to taxane during neoadjuvant chemotherapy (NAC) and poor outcome. In the present study, we evaluated the clinical significance of BRCAness in a multicenter retrospective study. Methods: The data on 94 patients with TNBC treated with NAC were obtained from 3 hospitals in Japan. Most of them were treated by anthracyclines plus taxanes in 86 patients between 2005 and 2015. BRCAness was determined by core needle biopsy (CNB) specimens prior to NAC and surgical specimens. Genes from those specimens were amplifie...