Research in our laboratory focuses on the engineering of protein-based therapeutic and diagnostic agents. This research combines chemical, cell biological and molecular biological techniques. We aim at constructing large repertoires of mutant proteins, from which proteins with the desired phenotype (e.g., binders or catalysts) can be selected. Typically, these agents are then chemically modified for biomedical applications. Particular attention is dedicated to the development of tumour targeting agents, and to the discovery of novel markers of pathology.