In the past, research in cancer immunology has produced informa tion important for other medical disciplines. It helped, for example, in formulating the laws of immunogenetics and in achieving a better understanding of the mechanism governing the fate of allotrans planted tissue. Cancer has often been considered a foreign body, and therefore many attempts have been made to cure it on the basis of the immunological principles applicable to parasitic, bacterial, or viral diseases. Vaccination has been investigated clinically for its po tential to prevent cancer 1], and clinical research into...