The identification in 1982 of a mutation in the Ha-ras gene provided the first indication of a link between specific molecular changes in regulatory proteins and cancer. 1-3 The mutant ras protein, in which valine replaces glycine-12, was shown capable of inducing morphological changes in mouse fibroblast (NIH-3T3) cells. In these cells the transformed phenotype is indicative of oncogenic activation and correlates with increased ...
