Collagens XV and XVIII are basement membrane associated collagens that can be cleaved to generate the antiangiogenic peptides restin (endostatin-XV) and endostatin (endostatin-XVIII), respectively (O'Reilly et al. 1997, Ramachandran et al. 1997, Sasaki et al. 2000). Endostatin fragments of differing molecular size (14-30 kDa) have been identified in vivo. Furthermore the C-terminal domains of several other collagens (IV, VIII, XIX) have anti-angiogenic and anti-tumoral activities (Ricard-Blum & Ballut 2011). Several proteases are able to generate endostatin from collagen XVIII including MMP-3, -7, -9, -13 and -20 and cathepsins B, V, S and L (Heljasvaara et al. 2005, Ma et al. 2007, Veillard et al. 2011). Endostatin inhibits proliferation of endothelial cells, angiogenesis and tumor growth in vivo (O'Reilly et al. 1997).