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Journal of Drug Delivery
Volume 2017, Article ID 6971297, 22 pages
Review Article

Targeted Delivery of siRNA Therapeutics to Malignant Tumors

1Department of Pathology, University of Maryland School of Medicine, 10 S. Pine St., Baltimore, MD 21201, USA
2Aparna Biosciences Corporation, 9119 Gaither Rd., Gaithersburg, MD 20877, USA

Correspondence should be addressed to A. James Mixson; ude.dnalyramu@nosxima

Received 31 August 2017; Accepted 10 October 2017; Published 9 November 2017

Academic Editor: Ambikanandan Misra

Copyright © 2017 Qixin Leng et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Over the past 20 years, a diverse group of ligands targeting surface biomarkers or receptors has been identified with several investigated to target siRNA to tumors. Many approaches to developing tumor-homing peptides, RNA and DNA aptamers, and single-chain variable fragment antibodies by using phage display, in vitro evolution, and recombinant antibody methods could not have been imagined by researchers in the 1980s. Despite these many scientific advances, there is no reason to expect that the ligand field will not continue to evolve. From development of ligands based on novel or existing biomarkers to linking ligands to drugs and gene and antisense delivery systems, several fields have coalesced to facilitate ligand-directed siRNA therapeutics. In this review, we discuss the major categories of ligand-targeted siRNA therapeutics for tumors, as well as the different strategies to identify new ligands.