On the other hand, EVs from the HER2-positive breast cancer cells were significantly enriched in proteins that function in cell–cell adhesion, translation initiation and the ERBB2 signaling pathway, which reflect the biology of HER2 tumors and their proliferative nature, as evident by the strong enrichment in terms related to increased protein synthesis, a process that has been associated with cell proliferation, a hallmark that is common to HER2-positive tumors13,34,35. Here, ERBB2 is linked to breast cancer.