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 against their tumor cells that results in tumor regression. Based
on the recent advances in our understanding of the compo nents of our immune system their
interactions and the regulation of immune responses we are now able to design vaccination
strategies that induce or enhance cell-mediated immunity against tumors. A ma jor advancement
came with the identification and characterization of relevant tumor antigens which are
suitable target structures for anti-tu mor immune response. First clinical trials using such
vaccine strategies have yielded encouraging results in patients. However in spite of many
reported cases of successful therapy of cancer by vaccination many patients still do not
experience relief after such treatments. These initial clinical trials and the accompanying
investigations have revealed a number of important results that indicate the direction of
future re search and development in the field.
