Others have reported CD63, ALG-2-interacting protein X (Alix), which is involved in exosome biogenesis and endosomal sorting [86, 87], and TSG101, or a combination of these proteins, from MDA-MB-231, MCF-7, T47D:A18, and Hs-578T breast cancer-derived exosomes [37, 45, 49, 50]. Here, CD63 is linked to breast cancer.