HSPG2 and neoplasm: In addition to a well-established role in development [20,23,26,104,165,166,167], HSPG-ligand interactions play major roles in tumor stroma and tumor microenvironment by regulating cellular proliferation, differentiation, adhesion, migration, apoptosis, angiogenesis, inflammation, invasion, and metastasis [3,22,24,25,28,33,34,35,36,37,38,39,40,107,143,165,168] (Figure 1).