Recently, monoclonal antibodies have been developed which can mark tumor cells on the outside by binding to specific proteins (receptors). The antibody makes the tumor cell recognizable for the immune cell attack. By another approach, certain antibodies target and destroy proteins in the circulation that make the cancer grow.
Concerning the terminology, monoclonal antibodies can be recognized by the suffix -mab in the drug's name.
For more information refer to the monoclonal antibody section of the Formularium.