Syndecan-1, a cell surface heparan sulfate proteoglycan, has been shown to play an important role in the VM process of melanoma CSCs [300]; moreover, Shih et al. recently demonstrated that the heparan sulfate binding angiopoietin-like 4 (ANGPTL4) protein, highly expressed in melanoma CSCs, is deeply involved in the tube-forming ability of these cells in vitro [301]. This evidence concerns the gene CD44 and melanoma.