Originally described in melanoma cells, glycoprotein nonmetastatic melanoma B (Gpnmb), also known as osteoactivin and dendritic cell-associated heparin sulfate proteoglycan-dependent integrin ligand, is a heavily N-glycosylated type I transmembrane domain protein with a short cytoplasmic domain containing an endosomal sorting motif [12–14]. This evidence concerns the gene GPNMB and melanoma.