ERBB2 and carcinoma: Marchio et al. identified 4% (2 of 45) ISH group 4 and IHC2+ carcinomas as HER2-enriched subtype by the Prosigna assay.8 This observation together with our limited observations on survival and recurrence in trastuzumab-treated patients and Marchio et al.’s preliminary observation on pathologic response after neoadjuvant trastuzumab suggests that even though these tumors are rare the possibility of benefit from anti-HER2 treatment in some of these tumors is worth investigating.