Angiogenesis (formation of new vessels from pre-existing ones) is a crucial early event in the process of tumor development. New vessels supply the tumor with nutrients that are needed for further local growth and enable distant metastases (Folkman 1995). Judah Folkman (1971) highlighted the potential therapeutic imp- cations of tumor angiogenesis. He hypothesized that if tumor angiogenesis is inhibited, then tumor growth and metastasis will be impaired greatly or even impossible. The subsequent quest for endogenous and exogenous inhibitors of angiogenesis has yielded a variety of promising...