Abstract P5 06 01: Homologous recombination deficiency (HRD) score predicts response to standard neoadjuvant chemotherapy in patients with triple negative or BRCA1/2 mutation …

Background: Defects in the homologous recombination (HR) DNA repair pathway sensitize tumors to therapeutics that target this pathway. A significant proportion of triple negative breast cancers (TNBC) carry HR defects. Recently three DNA-based measures (LOH, Abkevich et al.; TAI, Birkbak et al; LST, Popova et al.) have been developed and shown to be highly associated with BRCA1/2 mutation status and sensitivity to platinum-based chemotherapy in TNBC. Standard chemotherapy consists of some combination of an anthracycline and cyclophosphamide, with or without a taxane. This study assesses the association of LOH, TAI, LST and the sum of these measures, the HRD Score, with response to standard neoadjuvant chemotherapy in patients with TNBC.Methods: Tumor samples were retrospectively obtained from 45 TNBC patients and 2 BRCA1/2 mutation positive hormone receptor-positive/HER2 …