Immunotoxin therapy of cancer.

Differentiation antigens, hormones and growth factor receptors, and viral antigens are expressed on the surface of a variety of malignant and dysfunctional cells in humans. Murine and human monoclonal antibodies, recombinant hormone and growth factors, and recombinant soluble viral glycoprotein receptors have been generated that can target diseased human cells in vitro and in vivo. Highly potent peptide toxins that catalytically inactivate protein synthesis have been linked both chemically and genetically to these ligands to produce a new class of cancer therapeutic agents called immunotoxins. This article describes the structure, physiology, and initial clinical results with these molecules. Ongoing clinical studies are beginning to define a role for these unique agents in patients with malignancies of minimal bulk in combination with conventional chemoradiotherapy.