Both over-expression and silencing (Figure 3) of the heparanase gene clearly indicate that heparanase not only enhances cell dissemination but also promotes the establishment of a vascular network that accelerates primary tumor growth and provides a gateway for invading metastatic cells.16 While these studies provided a proof-of-concept for the prometastatic and proangiogenic capacity of heparanase, the clinical significance of the enzyme in tumor progression emerged from a systematic evaluation of heparanase expression in primary human tumors. The gene discussed is HPSE; the disease is neoplasm.