The pivotal role of Ras as a transducer of vital signals is well established. As such, aberrant Ras signaling is associated with cancer, neurofibromatosis, and Alzheimer's disease. This realization could make detection of mutated ras a useful diagnostic and prognostic tool. Exploiting the biochemical properties of Ras has made interfering with Ras activity a potential clinical option and dissection of the relative contribution of each signaling pathway emanating from Ras will certainly provide additional targets for clinical intervention. © 1996 Elsevier Inc. All rights reserved.