[Growth factors--clarification of their mechanism].

Every cell possesses a complex network of proteins that regulate its fundamental life processes. Growth factors act on specific cell surface receptors that activate these proteins, thereby regulating cell division, cell differentiation, or apoptosis. A cascade of protein phosphorylation reactions, ultimately resulting in the activation of gene transcription, is a common feature. Many of the proteins involved in the actions of growth factors have mutated variants that act as oncogenes. Although our knowledge of the mechanisms involved in growth factor action and in the development of malignancy is rapidly expanding, the route toward its utilisation in new therapeutic approaches will be long and arduous.