Angiogenesis research began with the question of how tumors induce the formation of blood vessels (angiogenesis). The background: solid tumors can only grow to a few cubic millimeters in size if they are not being nourished through blood vessels. If the supply of nutrients and oxygen by means of diffusion ceases, any further tumor growth is dependent on blood vessels. Folkman began dealing with this in detail in the early seventies. Although only a few people were working in this field at that time, by the late eighties and early nineties much greater interest was being shown. Meanwhile, numerous factors have been discovered that stimulate the formation of blood vessels. Several of these factors can be produced by the tumor cells themselves.

The main significance of the research findings is for cancer therapy applications, because if it becomes possible to inhibit or prevent the creation of blood vessels, the growth of tumors will be stopped. Or to put it another way, the tumor starves. Numerous research groups are trying out different approaches to block the process of angiogenesis.