Raf pathway inhibitors in oncology.

Recognition of the importance of the Raf pathway in the proliferation and survival of tumor cells recently increased with the discovery of activating BRAF mutations in human tumors. Therefore, in addition to a role in controlling tumors with Ras mutations and activated growth factor receptors, inhibitors of the Raf pathway may harbor therapeutic potential in tumors carrying a BRAF oncogene. A variety of agents have been discovered that interfere with the Raf pathway, including antisense oligonucleotides and small molecules. These inhibitors block the expression of Raf protein, block Ras/Raf interaction, block its kinase activity, or block the kinase activity of the Raf target protein mitogen-activated protein kinase kinase. Raf pathway inhibitors that are currently undergoing clinical evaluation show promising signs of anticancer efficacy with a very tolerable safety profile. Indeed, the Raf inhibitor BAY-43-9006 recently entered phase III clinical trials. Here, we review the current development status of potential Raf pathway therapeutics.