Current perspectives on immunotherapy for colorectal cancer.

Colorectal cancer immunotherapy is currently under investigation as a potential adjuvant treatment. There are a number of approaches that come under this heading. Active nonspecific immunotherapy aims to stimulate the immune system as a whole, without targeting any individual tumor-associated antigen (TAA), while adoptive immunotherapy takes either tumor-infiltrating or peripheral blood lymphocytes and stimulates them with cytokine prior to reinfusion back into the patient. Monoclonal antibodies are designed to target specific TAA and cause tumor cell death by apoptosis, antibody-dependent cell-mediated cytotoxicity or complement. The most diverse approach, however, involves attempting to stimulate the immune system to target cancer cells and is known as active specific immunotherapy. This includes peptide vaccines, anti-idiotypic antibodies, mucin, DNA/RNA (polynucleotide-mediated immunization) and heat shock protein-based vaccines, as well as viral vectors.