The immune system is in effect, comprised of a network of cells specialized to defend the body against antigens, or foreign invaders, including viruses, parasites, and bacteria, or any other foreign substance. Antibodies are an important part of the immune system, and they are proteins. The immune system makes protein antibodies to attach to the antigens (foreign invaders) which are most frequently to be found on the surface of cells. Then those antigens can then be identified and then destroyed by antibodies or other protecting cells in the immune system. Antibodies, specifically monoclonal antibodies, hold great promise in assisting in the treatment of cancer.Monoclonal AntibodiesMonoclonal antibodies (also referred to as MAOB’s’s or MAB’s) can often work on cancer cells in the same way a person’s natural antibodies work, and that is, by identifying and binding to the target cells, the cells that need attacking. The monoclonal antibodies then alert other cells in the immune system to the presence of the cancer cells in the body. MAB’s (or MAOB’s) are chosen specifically for a particular antigen - that is to say, a monoclonal antibody that is designed for a certain type of lymphoma will not work on cells for breast cancer cells, for example.

MAB’s (MAOB’s) are classified as Biological Response Modifiers. Since these antibodies affect the immune system, treatment with monoclonal antibodies is called immunotherapy, as opposed to the other treatments such as chemotherapy, which is therapy with drugs which tend to interfere in cancerous cell growth.

Researchers make MAOB’s by injecting human cancer cells into mice so that the mice’s immune systems will make antibodies against these cancer cells. Then, researchers remove the mouse cells that are producing these antibodies and fuse them with a laboratory grown cell (also known as an “immortal” cell) to create a "hybrid" cell called a hybridoma. Hybridomas are capable of producing, indefinitely, large quantities of these pure monoclonal antibodies for treatment against cancer. MAOB’s, by themselves, have the potential to enhance a patient's own natural immune response to the cancer. Some antitumor effects have been seen in the antibody treatment of certain cancers that include lymphoma, and some other cancers. But this monoclonal antibody treatment is not yet perfect. Sometimes the injected monoclonal antibodies produce no positive response or they may block a normal response in the patient. Cancer cells can also have an ability to hide their antigens, making themselves less likely to be destroyed my monoclonal antibodies. A way to increase the potential effectiveness of MAOB’s is to combine them with another form of therapy, such as radiation therapy or chemotherapy.For example, MAOB’s can be bound to a chemotherapy agent to enhance the effect of the chemotherapy. Through this combination of agents, two different mechanisms attack the cancer cell - the chemical from the chemotherapy and also the immune response from the MAOB. Chemotherapy can be more effective when the cancer cells are weakened by the monoclonal antibody (MAOB).Radiation therapy can also be combined with monoclonal antibody therapy. In this case, the monoclonal antibodies would be maid to contain a radioactive substance (such as radioactive iodine) that targets and destroys the cancer cells in the patient. With this form of combined therapy, the patient’s cancerous tumor cells receive a large amount of radiation while the patient’s normal healthy cell tissue is spared from damage. Radioisotope-labeled MAOB’s may also potentially prove useful in the process of diagnosing certain cancers.