When particular growth factors are bound to specific receptors on the surface of a cell, this can cause the cell to propagate itself and build certain tissue similar to blood vessels. Worldwide, research into receptors has focused on a special class of proteins, called tyrosine kinases. They are responsible for causing the received signal to be transduced through a long signalling cascade into the nucleus, triggering cell division and multiplication. Signalling cascades are absolutely necessary, if various tissues - like blood vessels, nerve tissue, and connective tissue - are to be built up during the development of an organism and in the process of tissue regeneration.
Research has focussed on these tumour cell signalling cascades, because in cancers they are often disturbed. If there were a way to block growth factors, or the receptors on the cellular surface from tumour cells, that could lead to targeted therapies against cancers. Already in the 1980s, cancer researcher Axel Ullrich, then a scientist at Genentech (USA), working with colleagues in the UK and Israel, succeeded in describing the structure and function of a receptor for epidermal growth factor (EGF). Since then, tyrosine kinases and various growth factors have been at the focus of research and development of therapies against tumours.
Also, over a decade ago, a team led by Ullrich discovered that by interrupting the oxygen and nutrient supply to tumour cells, it is possible to inhibit