The present invention provides a method for inhibiting the proliferation of malignant and/or hyperplastic cells in a subject by administering to the subject a therapeutically effective amount of a guanosine rich oligonucleotide. The present invention also provides oligonucleotides which are capable of being specifically bound to a specific cellular protein which is nucleolin and/or nucleolin-like in nature, which is implicated in the proliferation of cells, specifically malignant and/or hyperplastic cells, and a method for their selection.