A recombinant human proteolytic fragment of the C-terminal end of type XVIII collagen. Endostatin induces microvascular endothelial cell apoptosis and inhibits endothelial proliferation and angiogenesis, which may result in a reduction in tumor burden. This agent also may decrease hepatic metastasis by inhibiting proinflammatory cytokines and vascular cell adhesion molecule (VCAM)-dependent cell attachment to the hepatic microvasculature.