Altering the rate of translation initiation of a specific gene can tightly regulate the synthesis of the corresponding polypeptide and is an important mechanism in the control of gene expression. For some time it has been known that many genes involved in cell proliferation, cell growth and apoptosis have atypical 5' untranslated regions (UTRs) containing a high degree of RNA secondary structure, upstream open reading frames and internal ribosome entry segments. These features play a key role in the regulation of protein synthesis. In this review we discuss how the rate of translation initiation of proto-oncogenes and tumour suppressor genes is affected by elements in their 5' and 3' UTRs and we focus on how changes in the controlof gene expression at this level can contribute towards tumorigenesis.
