Ex vivo generated and tumor-antigen-loaded dendritic cells (DC) are currently used in clinical vaccination protocols in cancer patients. DC vaccines are safe, with minimal side effects. Evaluating more than 200 patients treated the past ten years we found that clinical responses measured in several patients directly coincide with specific cytotoxic T cell responses. The majority of studies investigated the therapeutic effects of DC vaccines in late-stage cancer patients with metastasis. In these (heavily) pretreated patients the immune system is compromised. Based on our observations that a specific immune response is indicative for a good clinical outcome we believe that the full potential of these immunostimulatory cells has to be exploited in high-risk patients with low tumor burden or in a precancerous state.