Novel immunotherapeutic approaches to prostate cancer

Immunotherapy offers new and exciting therapeutic options for patients with late-stage prostate cancer. While the concept of using the immune system to combat cancer is not new, it is only in this post-genomics era that the realistic possibility exists of effectively harnessing the immune system against disease. Immunotherapies can be loosely divided into three major categories: non-specific immune stimulation, specific target antigens and whole-cell approaches. All three systems have merits and drawbacks, although the goal of overcoming 'self' tolerance is common to all of them. This review highlights some of the more recent experiments in each of these three fields, focusing particularly on prostate cancer. We suggest that it is unlikely that one single cancer antigen exists and that recent data support this by showing that strong immune responses to prostate antigens can be elicited in a variety of ways. Therefore, a multivalent approach is likely to be most clinically efficacious. Data gathered from the past three years are discussed in this review and lead to the inescapable conclusion that immunotherapy is now a reality.