Harnessing the immune system for ovarian cancer therapy

The clinical course of ovarian cancer is often marked by periods of relapse and remission until chemo-resistance develops. Patients in remission with minimal disease burdens are ideally suited for the evaluation of immune-based strategies. Major obstacles to the development of successful immune strategies include the identification of tumor-restricted immunogenic targets, generation of a sufficient immune response to cause tumor rejection, and approaches to overcome evasion of immune attack. Many questions remain as optimal strategies are developed, which include: (i) What is the best antigen form (e.g. peptides, proteins or tumor lysates)? (ii) What are the appropriate adjuvants? (iii) Are mono-valent or multi-valent vaccines likely to be more effective? (iv) What is the optimal frequency and duration of vaccination? (v) How should antigen-specific responses be monitored? and (vi) How should the anti-cancer response be maintained? In this review, we explore representative examples of immune strategies under investigation for patients with ovarian carcinoma which illustrate many of these issues. Basic principles generic to all these immunotherapeutic approaches will also be discussed.