Decades of genetics research have employed both germline andconditionalallele manipulations of RAF isoforms; these studies have revealedboth redundancy and distinct functions for BRAF and CRAF in differentcell types and stages of cancer progression.47−50 Recent genetic ablation of CRAFsuggested that removal of the protein may afford a therapeutic benefit.45,51 However, as no well-characterized CRAF-selective inhibitors havebeen reported, the consequences of selective CRAF inhibition haveremained unknown. The gene discussed is RAF1; the disease is cancer.