The tyrosine kinases are frequently implicated in experimental as well as in human cancer. The best-studied receptor signaling system from this family is the EGF receptor. Experts in this area report on the involvement of the receptor in a variety of human tumors, outline underlying molecular mechanisms for aberrant receptor signaling in experimental systems and present the status of current therapies. A detailed analysis of EGF receptor signal transduction via expression of receptor, ligands, phosphatases and presence of other members of the receptor family will provide new information for...