HPSE and plasma cell myeloma: Activation of genes that are associated with high heparanase expression in myeloma patients such as Notch, Sonic Hedgehog, Smad and the Tor complex C1 (Figure 2 and Figure 3) are among the major regulators of cancer stem cell activities, and their alterations are associated with tumorigenesis in myeloma [54,55,56,57,58].