Nucleic acid aptamers in cancer medicine.

Many signalling proteins involved in diverse functions such as cell growth and di¡erentiation can act as oncogenes and cause cellular transformation. These molecules represent attractive targets for cancer diagnosis or therapy and are therefore subject to intensive investigation. Aptamers are small nucleic acid molecules, isolated from combinatorial libraries by a procedure termed SELEX, that bind to a target molecule by providing a limited number of speci¢c contact points embedded in a larger, de¢ned three-dimensional structure. In some cases aptamers have the potential to inhibit the biological function of the molecule resulting in useful reagents for target validation in a variety of disease models.