Antibodies are ideally suited for eradicating pathogens from the bloodstream and early tissue invasion. With regard to cancer cells, passively administered and vaccine induced antibodies have accomplished this, eliminating circulating tumor cells and systemic or intraperitoneal micrometastases in a variety of preclinical models. A series of cancer cell-surface differentiation antigens have now been identified and synthesized. Antibodies against each can be induced in most vaccinated patients using keyhole limpet hemocyanin conjugate vaccines with a potent immunological adjuvant. Polyvalent vaccines may be required due to tumor cell heterogenely, heterogeneity of the human immune response and the correlation between overall antibody titer against tumor cells and antibody effector mechanisms. Trials testing the clinical impact of these polyvalent vaccines in the adjuvant setting are planned for the near future.