In summary, we have demonstrated that trastuzumab upregulates PERP, ITB1, GNAS2, and GNA13 in EVs emitted by two different trastuzumab-sensitive breast cancer cell lines but not in EVs derived from two different trastuzumab-resistant breast cancer cell lines (Figs. 2, 3, 4, and 5). Here, PERP is linked to breast cancer.