ABCB1 and cancer: Release of multidrug resistance protein 1/P-glycoprotein (MDR-1/P-gp), a transporter protein that is associated with the efflux of many foreign substances including anti-cancer drugs from exosomes, was a likely factor in conferring resistance to the docetaxel-sensitive cells after the authors treated the cells with exosomes obtained from docetaxel-resistant variants of DU145 and 22Rv1 (DU145RD and 22Rv1RD), respectively [147].