There are good reasons to think the immune system helps in the fight against cancer. For instance, people with weakened immune systems are more likely to get certain cancers. But many people with normal immune systems still develop cancer. This may be because the immune system doesn't see the cancer cells as foreign. Often, this is because the cancer cells (and their antigens) are not different enough from those of normal cells. Sometimes the immune system recognizes the cancer cells, but the response may not be strong enough to destroy the cancer. Cancer cells themselves may also give off substances that keep the immune system in check.

To overcome this, researchers have designed ways to help the immune system recognize cancer cells and strengthen its response so that it will destroy the cancer.

There are 2 main types of immunotherapy. Active immunotherapies stimulate your body's own immune system to fight the disease. Passive immunotherapies do not rely on your body to start the attack on the disease; instead, they use immune system components (such as antibodies) made in the lab. We will be talking about both types here.

Another way that immunotherapies can be understood is based on whether or not they target a certain type of cell. Most of the immunotherapies being used today target one kind of cell or antigen (specific immunotherapies), but there are some that stimulate the immune system in general. These are called non-specific immunotherapies. Sometimes non-specific immunotherapies are used with other treatments to help increase the attack on the cancer. These kinds of treatments are generally only used along with other treatments, so they are called adjuvants.

There are other treatments that target one type of cell and don't tend to damage other cells, which are also called targeted therapies. For more information see our document, Targeted Therapies.

The types of immunotherapy described in the following sections include:

• monoclonal antibodies (passive immunotherapies)
• other targeted therapies that carry toxins to cancer cells (passive immunotherapies)
• cancer vaccines and other active immunotherapies
• non-specific immunotherapies and adjuvants

The last section covers some types of cancer in which immunotherapies are used, and which kinds are used to treat them.

Go back to Immunotherapy.

Last Medical Review: 08/25/2009
Last Revised: 08/25/2009