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Immunotherapy Overview The basic idea of immunotherapy is to try to get your immune system to react to your tumor as if it were foreign. An antigen is a substance that when introduced into the body elicits an immune reaction. When you get a flu shot, you're being given a tiny amount of the proteins that are found in common flu viruses. You run a slight fever after the shot because these antigens are causing an immune response, and antibodies are being produced in response to the presence of the antigens. Most people don't get sick from the vaccine because it is such a small amount. If you later exposed to the flu that would normally make you very ill, you have a head start in making antibodies to fight the infection and you typically don't get sick.
Dr. Keohan, in her article "What is immunotherapy and what role does it play in cancer treatment" that appeared in the April 2004 issue of ESUN, states, "Cancer cells have substances on their outer surfaces that can act as antigens and thus “mark” the cells as different or abnormal. Viruses, bacteria, and parasites have cells that are substantially different from normal human cells because they are truly foreign to the body and are detected by the immune system. However, the differences between cancer cells and normal human cells may be more difficult for the immune system to detect. Cancer immunotherapies are designed to help the immune system recognize cancer cells and/or to strengthen the immune response to the cancer cells and thus destroy the cancer. The cancer cells’ antigens may not be different enough from those of normal cells to cause an immune reaction; thus, the immune system may not recognize the cancer cells as foreign. The immune system may recognize the cancer cells’ antigens, but the immune response may not be strong enough to destroy the cancer. Additionally, some cancer cells themselves may also give off substances that prevent the immune system from responding properly." She goes on to say, "There are two broad classes of immunotherapies, active immunotherapy and passive immunotherapy. Active immunotherapies stimulate the body’s own immune system to fight the disease. Passive immunotherapies do not rely on the immune system to attack the disease; instead, they use immune system components (such as antibodies) that are created outside of the body to fight the disease. These two approaches are also called vaccine therapy and antibody therapy respectively. In vaccine therapy, or active therapy, the patient is given a vaccine that should stimulate the immune system to attack the cancer. In antibody therapy, or passive therapy, the patient is given antibodies that will hopefully target the cancer but leave the non-cancerous cells alone. The problem with both approaches is finding substances that the immune system can target (antigens) which are only present on the cancer cells and not on normal cells. Sometimes vaccines combined with nonspecific immunotherapy, using additional substances or cells called adjuvants in order to boost the immune system’s response. Doctors may employ two or more of these immunotherapy options together." There are several different types of vaccines. Among them are tumor cell vaccines, dendritic cell vaccines, antigen vaccines, anti-idiotype vaccines, and DNA vaccines.
Useful Material We recommend reading the article "Genetic, Cellular and Immune Approaches to Disease Therapy: Past and Future" that appeared in Nature Medicine. The National Cancer Institute (NCI) has a good tutorial on "The Immune System". NCI's "Cancer Vaccine Primer" and the companion article, "NCI Pursues Vaccine to Prevent and Treat Cancer" are worth reading. Finally the Research Corner News column of the April 2004 issue of ESUN has a number of useful immunotherapy references. The Liddy Shriver Sarcoma Initiative is currently sponsoring two research grants that deal with vaccine-based approaches for treating sarcoma. See our Funded Research page for details.
Additional Background linksAdditional General Immunotherapy Links
Some Links Dealing with Sarcoma and Immunotherapy
Dendritic Cell Links for Sarcoma
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