The induction of immune responses against tumor cells by vaccination is rapidly evolving as a therapeutic modality with new potentials for the treatment of cancer. It is based on the fact that our immune system can identify tumor cells and, once activated, is capable of developing specific immunity against the neoplastic cells. Numerous observations and intense research clearly document the major contribution of the immune system to the prevention of cancer. And there are many re ports of patients suffering from malignant melanoma or other tumors who mount a spontaneous immune response...