The existence of immunity to cancer was postulated by the eminent scientists who helped to establish the discipline of immunology. In 1907 Clowes suggested that human resistance to cancer resulted from what we today call “immune surveillance.” During the ensuing 70 years the results obtained from experimental animal cancers and human cancers have greatly influenced the palatability of tumor-immunity theories. Early optimism that immunity to cancer could be specifically induced waned and almost disappeared when it was demonstrated that the rejection of cancer transplants resulted from transplantation immunity and not tumor immunity. A sustained wave of enthusiasm for immunity to cancer appeared after demonstrations that inbred animals could be immunized to cancers arising in the inbred strain
