The preceding article focused on some novel approaches for the adjuvant treatment of human melanoma and neuroblastoma with mAbs against antigens preferentially expressed on these tumors. It should be emphasized that the major goal of the immunotherapy modalities described here is to apply them in an adjuvant setting for the treatment of micrometastases. The major aim is to decrease the rate of development of metastases in a setting of very low tumor burden and ultimately achieve a prolongation in life span. The combination of powerful modern technologies achieving genetic engineering of mAbs, resulting in more human-like molecules, will lead to a reevaluation of these reagents alone or in combination with molecularly defined cytokines and growth factors for the immunotherapy of cancer. The initial, albeit anectodal, findings, of phase I clinical trials mentioned in this article lead to cautious optimism that immunotherapy may find a place and will eventually contribute to the adjuvant treatment of cancer.