The immunological bases of current approaches to therapeutic cancer vaccination (or ‘vacci-treatment’) have been established for a decade or longer. The new developments lie mostly in the lessons learnt from clinical testing of these approaches. Three lessons are particularly worthy of note. First, recently completed randomized Phase 3 trials suggest that vacci-treatment with autologous dendritic cells expressing prostatic acid phosphatase (for prostate cancer) or with autologous tumor-derived heat shock protein (gp96)–peptide complexes show promise in enhancing survival of cancer patients. These two approaches are undergoing further randomized clinical testing. Second, immunological monitoring of many clinical trials has failed to identify a surrogate marker for clinical outcomes. Finally, an increasing volume of literature suggests that protective immunity to human cancers is elicited by the mutated antigenic repertoire unique to each cancer.