What is a monoclonal antibody?
A monoclonal antibody is a laboratory-produced molecule that's carefully engineered to attach to specific defects in your cancer cells. Monoclonal antibodies mimic the antibodies your body naturally produces as part of your immune system's response to germs, vaccines and other invaders.
How do monoclonal antibody drugs work?
When a monoclonal antibody attaches to a cancer cell, it can:
Make the cancer cell more visible to the immune system. The immune system attacks foreign invaders in your body, but it doesn't always recognize cancer cells as enemies. A monoclonal antibody can be directed to attach to certain parts of a cancer cell. In this way, the antibody marks the cancer cell and makes it easier for the immune system to find.
Block growth signals. Chemicals called growth factors attach to receptors on the surface of normal cells and cancer cells, signaling the cells to grow. Certain cancer cells make extra copies of the growth factor receptor. This makes them grow faster than the normal cells. Monoclonal antibodies can block these receptors and prevent the growth signal from getting through.
Stop new blood vessels from forming. Cancer cells rely on blood vessels to bring them the oxygen and nutrients they need to grow. To attract blood vessels, cancer cells send out growth signals. Monoclonal antibodies that block these growth signals may help prevent a tumor from developing a blood supply, so that it remains small. Or in the case of a tumor with an already-established network of blood vessels, blocking the growth signals could cause the blood vessels to die and the tumor to shrink.
Deliver radiation to cancer cells. By combining a radioactive particle with a monoclonal antibody, doctors can deliver radiation directly to the cancer cells. This way, most of the surrounding healthy cells aren't damaged. Radiation-linked monoclonal antibodies deliver a low level of radiation over a longer period of time, which researchers believe is as effective as the more conventional high-dose external beam radiation.