Dendritic cell (DC)-based vaccination, usually administered by a traditional intradermal route, is a new treatment option for cancer patients. While the previous DC-based vaccination trials have shown the safety of this approach and its ability to induce objective clinical responses, the overall efficacy of DC-based vaccines is still disappointing (Rosenberg et al., 2004). We hypothesize that the two likely causes of such limited clinical activity are: A) suboptimal type of DCs used as a vaccine and B) suboptimal modes of use of such vaccines that do not allow the vaccinated patients to fully benefit from DC biology.