Recent progress in fundamental tumor immunology has led to immunotherapy trials in patients with solid tumors and hematological malignancies. In the past, immunotherapy approaches were primarily based on enhancement of tumor immunity with cytokines and adjuvant therapy, without knowledge of relevant tumor antigens. The discovery of tumor antigens capable of eliciting immune responses has now resulted in the development of antigen-specific immunotherapy strategies. Vaccination with defined peptide epitopes, purified proteins, cell components, and whole cells expressing defined tumor antigens...