Guilty as charged: B-RAF is a human oncogene

RAF proteins are components of a conserved signaling pathway that regulates cellular responses to extracellular signals. Despite over 20 years of research into the regulation and function of the RAF proteins, it was only realized recently that the B-RAF isoform is mutated at a high frequency in human cancer. Here we review the rapid progress made in our understanding of B-RAF as an oncogene and of its role in cancer.