AR and breast cancer: Seventy percent of the breast cancers that develop in women with inherited BRCA1 mutations are TNBC and 10–20% of women with TNBC have a BRCA1 mutation.14–16 Although outcomes after standard anthracycline-based adjuvant chemotherapy are similar for BRCA1 mutation carriers and noncarriers with TNBC, the BRCA1-associated TNBCs appear to be more responsive to platinum chemotherapy, likely due to their defect in homologous recombination.17–19 It is not known whether the frequency of AR and PD-L1 expression differs among TNBC in women according to BRCA1 status.