This SELEX experiment, for the selection of HER2 targeting aptamers, resulted in 26 selected RNA aptamers for further individual evaluation. Up till now, we were able to identify two aptamers that show binding to HER2 overexpressing SK-OV-3 cancer cells. In addition, we were able to generate silenced SK-OV-3 cells with minimal remaining HER2 levels, which will be used to obtain more information regarding the binding specificity of the selected aptamers.