Tyrosine kinase targets in drug discovery

Protein tyrosine kinases are central to the signal transduction machinery of healthy cells and their deregulation plays a causal role in many diseases, particularly in cancer. Inhibition of the altered activity of tyrosine kinases and restoration of physiological balance is being explored as a means of developing new therapeutic interventions. A number of small-molecule inhibitors and monoclonal antibodies, among other approaches, are currently being evaluated in cancer chemotherapy. The preclinical and clinical development of these agents, issues relevant to their progress and possible novel tyrosine kinase targets are discussed.