Challenges and opportunities of nanotechnology in cancer immunotherapy

Various strategies for cancer therapy have been devised over the past decade. Cancer immunotherapy has been an emerging technology that activates the host's immune systems to efficiently recognize and kill tumor cells. Despite the revolutionary development in the field of immunooncology, only a small fraction of patients have had beneficial results as many tumors possess the innate characteristic of immune evasion. Ideally, the immune system should be spatiotemporally regulated to augment the therapeutic index of these therapies. One method of enabling codelivery of immune-stimulatory molecules, improve pharmacokinetics and specificity to target sites, and reprogram tumor microenvironments is the utilization of nanoparticles. They have been shown to elicit enhanced antitumor immune responses that cannot be achieved by treating naked anticancer drugs. Immunotherapy harmonized with nanotechnology provides the tremendous opportunity to enhance the therapeutic effectiveness by delivering immunostimulatory molecules, adjuvantizing immune cells, and/or enabling specific targeting while minimizing side effects. Herein, we highlight how the convergence of cancer immunotherapy and nanotechnology overcomes the critical limitations of conventional treatments and increases the possibility for clinical translation in cancer treatments.