CD274 and breast carcinoma: These results indicate that PDCs exhibit significantly less targetable genetic alterations in contrast to related TNBC and metaplastic breast carcinomas.8, 9 A single case with a mutation in BRCA1 gene indicates a potential benefit to platinum compounds and PARP inhibitors.10 Tumor expression of PD‐L1 (TC) was negative/low in all but one case that exhibited 20% positive tumor cell population (Figure 1B), while IC expressing PD‐L1 were detected at potentially significant levels (IC2; ≥5%<50%) in three cases.