Targeting Immunotherapy to the Tumor Microenvironment.

Targeting drugs to the tumor microenvironment has long been appreciated as a means of increasing local concentrations and decreasing systemic toxicities. How drug targeting might apply to immune-based therapies is less clear. In this review, we explain the immunology of cancer, with a focus on the principles of in situ vaccination. Certain types of therapies are more amenable to local versus systemic delivery; these include cytokines, adjuvants, radiation, and agents targeting tumor-resident cell populations. Several approaches for targeting the tumor microenvironment are under development. Nanoparticles, peptide or antibody-based delivery, and exploitation of cellular influx are all promising ways to delivery immune modulating compounds to tumors. J. Cell. Biochem. 118: 3049-3054, 2017. © 2017 Wiley Periodicals, Inc.