The role of ras genes in the neoplasmic transformation in animals.

We can distinguish three kinds of ras genes i.e. H-ras, K-ras and N-ras, which are rated as ras-protooncogenes. The point mutations within ras genes are frequently detected in human malignancies and in experimentally induced tumors in animals. The aim of this article is to review briefly current research on the role and the frequency of ras gene mutational activation in naturally occurring animal tumors. The present studies show that the mutational activation of ras genes at the hot-spot loci in codons 12, 13 and 61 is apparently rare and does not perform an important role in the pathogenesis of naturally occurring tumors in animals. However, we cannot be sure if the mutational activation of ras genes occurs most often, but in other functional areas of these genes, or if there are other mechanisms involved in their activation.