The term immunotherapy in relation to cancer refers to processes that manipulate the immune system to improve the body’s response against a tumor. Immunotherapy has a long history and began in the era before the advent of cytotoxic drugs when cancer patients were treated with Coley’s toxin. This contained a mixture of killed Streptococcus pyogenes and Serratia marcescens bacteria that stimulated the immune system nonspecifically . The BCG vaccine, which contains killed mycobacteria, was used in the 1960s and 1970s, to treat malignant melanoma and has since been used to treat bladder cancer. Mycobacteria are potent stimulators of the immune response and increase the production of several cytokines, including interferon γ (IFN- γ) and tumor necrosis factor α (TNF- α). Nowadays, recombinant cytokines may be given directly to enhance the immune response. For example, interferon α (IFN- α) has been used successfully to treat multiple myeloma, CML, hairy cell leukemia and malignant melanoma. Interleukin 2 (IL-2) appears to exert an anticancer effect through the prolonged stimulation of Natural Killer cells; it has been used to treat renal cancer and malignant melanoma .
An exciting development in immunotherapy has been the production and clinical trials of a number of anticancer vaccines based on tumor associated antigens. Examples include vaccines based on peptides derived from carcinoembryonic antigens, and the BiovaxID™ vaccine for the treatment of follicular lymphoma, a type of nonHodgkin’s lymphoma involving B lymphocytes.