Abstract
In the pursuit of optimal anti-tumor immune effects, both “passive” and “active” immunotherapies have made significant progress recently. In situ vaccines offer a promising solution by using intratumoral administration of immunomodulators or other local treatments, to scientifically combine active and passive immunotherapies. It forms a repetitive cycle of immune initiation-immune effect-tumor cell death-antigen release, leading to immune re-initiation-immune re-effect. This cycle maximizes the anti-tumor immune effect. In this chapter, we highlight the specific strategies and promising preclinical results of in situ vaccine, along with ongoing clinical trials. We also discuss the advantages, challenges, and perspectives of this novel approach. Overall, in situ vaccine shows great promise in tumor inhibition and could be a valuable addition to the cancer immunotherapy armamentarium.