EV-delivered miR-181c from breast cancer cells downregulates 3-phosphoinositide-dependent protein kinase-1 (PDPK1) and disrupts the blood-brain barrier and consists of tight junctions between ECs and surrounding cells that contribute to low permeability and promote cancer metastasis in distant organs (Tominaga et al., 2015b). Here, PDPK1 is linked to breast carcinoma.