Immunotherapy with dendritic cells for prostate cancer.

Radical prostatectomy for prostate cancer is followed by PSA recurrence in up to 40% of patients. One third of patients with biochemical relapse progress to uncurable metastatic disease. Therefore, alternative treatment modalities are needed both in the situation of PSA recurrence and in hormone-refractory disease. Dendritic cells (DC) are the most powerful antigen-presenting cells, able to prime naïve T-cells and to break peripheral tolerance and thus induce tumor immune responses. More than 400 prostate cancer patients have been treated with DC-based immunotherapy to date, and immune responses have been reported in two-thirds of these, resulting in clinical responses in almost half of the patients treated. Most responses, however, were modest and transient. Therefore, mechanisms of treatment failure and possibilities to improve vaccination efficacy are being discussed.