CD63 and melanoma: Bead-based multiplex analysis revealed the robust expression of the sEV tetraspanins CD9, CD63, and CD81 in addition to CD29 (Integrin beta- 1), the MSC-EV-specific markers CD44 (hyaluronic acid receptor) and MSCP/NG2 (melanoma‐ associated chondroitin sulfate proteoglycan) (see Fig. 2).