Dendritic cells in cancer immunotherapy clinical trials: are we making progress?

Dendritic cells (DC) have been tested in cancer immunotherapy clinical trials for two decades. Over this time, the methods of DC culture (or manufacture) have evolved, the approaches for antigen loading have broadened, the maturation signals have varied and different sites of administration have been tested. The post-vaccination immunologic questions asked have also varied between trials and over time. In this review, I will consider multiple aspects of DC-based vaccines tested in cancer patients, including the cell culture, antigen loading, maturation, and delivery, as well as what we have learned from testing immune responses in vaccinated patients who have benefited clinically, and those who have not measurably benefited.