HGF and plasma cell myeloma: Syndecan-1 acts as a positive regulator of many effective molecules important for myeloma growth and survival, such as a proliferation-inducing ligand (APRIL), epidermal growth factor (EGF) family members, insulin-like growth factor (IGF), insulin-like growth factor binding proteins (IGFBP) or hepatocyte growth factor (HGF) and an inhibitor of human heparanase or heparinase III [13–18].