Drug discovery in oncology

A deeper understanding of the molecular events leading to tumour formation, invasion, angiogenesis, and metastasis has provided a new mechanistic basis for oncology drug discovery: targeted anticancer therapy. By specifically blocking the molecular pathways implicated in the pathogenesis of cancer, targeted anticancer agents are expected to alter the natural course of the disease and, at the same time, to offer an enhanced therapeutic index over traditional cytotoxic agents. Following this new paradigm, extracellular matrix remodelling enzymes, growth-factor receptors, signal transduction proteins, and regulators of cell-cycle and gene expression have been the subject of intense drug discovery activities. Three representative areas of research in which targeted cancer therapy has advanced with some success have been selected to briefly illustrate the current status and some of the challenges of drug discovery in oncology.