Advances of aptamer-based clinical applications for the diagnosis and therapy of cancer.

Aptamers are short single-stranded oligonucleotides that have attracted considerable attention due to their favorable biological characteristics. Aptamers can specifically target and bind to proteins or tumor cells, achieving tumor diagnosis and therapy in vitro and in vivo. Following an introduction of methodologies of producing aptamers and the recent advances of aptamers being applied to clinical samples or xenograft tumors, tumor diagnosis using aptamers will be reviewed, including fluorescence imaging, radionuclide-based imaging, MRI, histochemical imaging, and multimodality imaging. Preclinical applications in tumor therapy in vivo will also be discussed, covering different kinds of treatment mechanisms, including aptamer therapeutics, chemotherapy, gene therapy, immunotherapy, and combination therapy. Safety and efficacy of tumor-targeting therapeutics via aptamers, as well as the current challenges and future perspectives about aptamers' clinical applications, will be summarized.