Endostatin is a cleaved product of the carboxyl-terminal domain of collagen XVIII. It functions as an anti-angiogenic cytokine that is expressed in various organs especially with high levels in liver, lung, and kidney. Endostatin inhibits angiogenesis by blocking the pro-angiogenic activities of VEGF and FGF-basic. Recombinant Endostatin expressed in yeast, whichcauses G1 arrest of endothelial cells. Endostatin treatment results in apoptosis of HUVE and HMVE cells. Recombinant human Endostatin is a 20.2 kDa protein consisting of 184 amino acid residues.