The identification of a molecular target for angiostatin, a protein fragment of plasminogen that inhibits angiogenesis by blocking endothelial cell proliferation and migration, could allow small molecules to be developed that bind the target and prevent the process that enables tumors to expand.

This would solve the problems of developing a manufacturing method to produce the protein, which has been difficult. However, angiostatin's cell surface target, ATP synthase, is a widely required protein inside of cells. Thus small molecules binding the target may be toxic to cells and