Monoclonal antibodies are monospecific antibodies produced from identical immune cells that are clones of a single parent cell. They are used widely for diagnostic and therapeutic purposes. Monoclonal antibodies can be used to treat cancer through several mechanisms, including antibody-dependent cell-mediated cytotoxicity, radioimmunotherapy, and by delivering drugs or toxins directly to tumor cells when conjugated to monoclonal antibodies that target tumor antigens. The types of monoclonal antibodies include murine, chimeric, humanized, and fully human antibodies produced through various technologies to reduce immunogenicity.