ERBB2 and breast cancer: Prompted by the increasing findings on differences in EVs from different tissues of origin and their potential for BC diagnosis, monitoring, and response to therapy, we investigated the proteomic profile of breast FADs and the possible relationship with BC–derived EVs using high–throughput proteomics, comparing the EV proteomes of two patient-resected FADs and two distinct BC subtypes (i.e., HER2+ BC and TNBC) along with three IBCC lines (i.e., BT–549, MCF–10A, and MDA–MB–231).