" In the management of cancer, a big problem with traditional methods has been that the patient can perceive the treatment as almost worse than the disease, since the chemicals given to attack the cancer cells also attack many other types of cell. In the frontline of cancer drug development today is a sophisticated range of drugs with names ending in ‘mab’, standing for monoclonal antibody. One half of the therapeutic molecule is an antibody against specific proteins on the surface of the target cancer cells and the other half is an enzyme. (This strategy relies on the surprising fact that, often, if the genes for two proteins are joined end to end, they successfully encode an enlarged protein combining both functions—i.e. both halves still fold successfully.) When this delivery vehicle reaches its destination, the whole molecule is taken up into the cells. The other half, chemically attached to the antibody, is the enzyme ‘warhead’ that inflicts the damage. The enzyme itself could be one that, for example, attacks the cells’ nucleic acids. "

― , Enzymes: A Very Short Introduction