Dendritic Cell Therapy in Immuno-Oncology: A Potentially Key Component of Anti-Cancer Immunotherapies

Dendritic cells (DCs) are a heterogeneous population known for antigen presentation and immune modulation, playing a key role in priming a T cell response against pathogens and tumor cells. Despite their putative therapeutic value, their scarcity in peripheral blood limited their direct use in therapeutic applications until recently. The discovery that DCs can be generated from circulating monocytes ex vivo, however, gave a boost of extensive research in the use of DCs in clinical applications. Still, despite the numerous clinical trials, the introduction of DCs in the everyday clinical oncology practice is delayed. In this narrative review, we provide an updated summary of the field covering the theoretical and practical aspects of the concept of the use of DCs in adoptive cellular immunotherapy and the completed or ongoing clinical trials for the use of these species in clinical oncology practice. To better understand the current developments of the field, we included those clinical trial reports that published evaluable data to date. Based on our literature survey, DC-based adoptive cellular therapy is a safe therapeutic intervention with valuable clinical potential. Its widespread implementation, however, is likely delayed due to a number of factors that make meaningful evaluation of clinical trial results complicated. These include the great variety of preclinical trial concepts, difficult and heterogenous patient cohorts, and the diversity of intervention techniques applied. Since these factors might hinder the routine implementation of DC-based applications in the more widespread forms of immunotherapy, one of the urgent short-term future directions seems to be the standardization of the DC-based methodologies.