CD44 and melanoma: Other proteins are also enriched in malignant melanoma cell-derived exosomes, indicating their importance to melanoma development; these include tyrosinase related protein 2 (TYRP2), HSP70, melanoma antigen recognized by T-cells 1 (MART1), major histocompatibility complex (MHC I), annexin A2, GTP-binding proteins, human epidermal growth factor receptor 2 (Her2/neu), CD44, GTP-binding proteins, and premelanosome protein (PMEL) [76,77,78].