Proposed involvement of heparanase in angiogenesis. Heparanase promotes: EC migration and degradation of the subendothelial basal lamina (BL) and ECM; release of active HS-bound bFGF and VEGF; and release of HS degradation fragments that promote FGF-receptor (FGFR) binding, dimerization, and signaling (arrows), inducing EC migration and proliferation.