treating many other kinds of tumors. Cancers of the colon, pancreas, stomach and esophagus, for example,
are not very sensitive to radiation. With more research it is hoped that this technique may soon have
better success.
• In the same way, MAbs that are specific against a certain cancer can be programmed to deliver other anticancer
agents such as chemotherapy drugs or cell toxins like ricin to the tumor. As with the radioactive-labeled
therapy, this is really antibody-guided treatment. The monoclonal antibody homes in on the cancer cell, latches
on to it and lets the payload of drugs or toxins do their work.
Problems and Promise Antibodies—Plain or bound to radioactive materials or other toxic substances—are being evaluated as therapy for cancer in clinical trials. The verdict on their usefulness isn’t in yet, though theoretically they have a potential for specifically targeting and destroying many tumor cells.
What is clear so far is that the success of antibody therapy depends on how specific the monoclonal antibody is against the target antigen on the surface of the tumor cell, on the blood supply to the cancer and on how any one person’s system handles the antibody. Unfortunately, there are still many problems to be overcome.
The major ones are damage to normal cells and the failure of MAbs to reach the tumor in sufficient amounts to destroy it. Repeated courses of MAbs can also cause allergic reactions, with symptoms including fever, chills itching, skin rashes, nausea, vomiting and flushing. A severe form of hypersensitvity known as serum sickness has also ben reported.
