A substance used in adjuvant therapy that takes advantage of the body’s own natural defense mechanisms to inhibit the growth of a tumor.

An agent or approach intended to modify the relationship between tumor and host by modifying a host’s biological response to tumor cells, with resultant therapeutic benefit. This includes agents or approaches which utilize or modify immunological mechanisms; naturally occurring or recombinantly produced regulatory molecules (e.g., cytokines, growth or differentiation factors); and monoclonal antibodies and their derivatives.