A new approach for anti-tumor immunotherapy is to use dendritic cells (DCs) as adjuvants in order to actively immunize cancer patients with antigens specifically expressed in tumor cells. DCs possess a unique capacity to effectively activate CD4+ T helper cells and CD8+ cytotoxic T cells. During the last years, several clinical trials in various malignancies demonstrated that immunizations with tumor antigen pulsed DCs could break the tolerance of the immune system against antigens expressed by the tumor cells resulting in partial or complete remission in some cases. This review describes the most important findings on the interaction between DCs and T cells as well as natural killer cells and summarizes recent data on DC vaccination of endocrine and non-endocrine malignancies. The results from current pilot studies suggest that DC vaccination may represent a promising strategy for the development of an anti-cancer vaccine to treat chemotherapy and radioresistant endocrine malignancies.