Clinical applications of nucleic acid aptamers in cancer

Nucleic acid aptamers are small single-stranded DNA or RNA oligonucleotide segments, which bind to their targets with high affinity and specificity via unique three-dimensional structures. Aptamers are generated by an iterative in vitro selection process, termed as systematic evolution of ligands by exponential enrichment. Owing to their specificity, non-immunogenicity, non-toxicity, easily modified chemical structure and wide range of targets, aptamers appear to be ideal candidates for various clinical applications (diagnosis or treatment), such as cell detection, target diagnosis, molecular imaging and drug delivery. Several aptamers have entered the clinical pipeline for applications in diseases such as macular degeneration, coronary artery bypass graft surgery and various types of cancer. The aim of this review was to summarize and highlight the clinical applications of aptamers in cancer diagnosis and treatment.