ONCOGENES AND TUMOR-SUPPRESSOR GENES - 2 DIFFERENT LOOKS OF THE SAME GENE

Dominant oncogenes and recessive tumor suppressor genes are widely imp licated in the pathogenesis of human neoplasia. Several recent experim ental findings suggested that an oncogene and a tumor suppressor gene can share a similar ontogeny from the parental normal 'in vivo' gene. At least three mechanisms have been demonstrated to be responsible for this ambivalent expression: the mutations located in different region s of the gene, transcriptional and post-transcriptional events (especi ally alternative splicing) and cell- and/or time-dependent control of gene expression. There are also evolutionary explanations for the exis tence of such genes with ambivalent expression.