The immune system is designed to fight and destroy invaders. It is normally able to differentiate between its own cells and foreign cells. A problem with cancer cells is that since they are a variation of normal cells, a healthy immune system does not always recognize them as foreign. Even when the immune system does recognize cancer cells, it may be too weak to fight them. The field of immunology strives to find identifying markers on cancer genes so that the immune system can be trained to fight the cancer cells. Through the Antigen Discovery Program, the Ludwig Institute for Cancer Research (LICR) has identified "a significant number of all known cancer antigens".
Identifying Cancer Antigens
Cancer antigens are molecules found on the surface of cancer cells. When the immune system recognizes these antigens as foreign invaders, it fights them. The problem arises when the immune system does not recognize the cancer antigens as foreign invaders. In order to teach the immune system to recognize cancer antigens, scientists must first identify them. Identifying antigens is the first step in the creation of cancer prevention and cancer treatment vaccines.
Lymphocytes are the cells that the immune system send out to fight antigens. Cancer vaccines teach the immune system to identify cancer antigens. The concept behind cancer vaccines is similar to the way a flu vaccine works. For a flu vaccine, a small amount of the virus is introduced into the body to teach lymphocytes to fight the viral invader.
Cancer Prevention Vaccines
Cancer prevention vaccines are designed to be given before an occurrence of cancer develops. The vaccine teaches the immune system to recognize and fight cancer cells should they develop in the future.
Cancer Treatment Vaccines
Cancer treatment vaccines are given after a patient has been diagnosed with cancer. The vaccine is designed to teach the immune system to fight the cancer cells that are currently attacking it and to prevent the recurrence of cancer.
Future of Cancer Immunology
Scientists are working on developing new cancer vaccines and new approaches to delivering the vaccines. Early research conducted at John Hopkins University showed that injecting an anti-cancer vaccine at the site of a cancerous tumor promoted immune response. In the United States, some cancer vaccines are now in the final stages of testing. One particular cancer vaccine that is in the final testing stages is one against prostate cancer. The vaccine consists of a weak virus that releases the prostate-specific antigen (PSA), which is an antigen of prostate cancer cells. The body fights the weak virus and learns to recognize cells with PSA as foreign, which in theory causes the immune system to fight prostate cancer cells before cancerous tumors can develop.
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LICR - Cancer Antigen Discovery Program
Controlled Release, Biodegradable Cytokine Depots: A New Approach in Cancer Vaccine Design, Department of Oncology, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205; Golumbek PT, Azhari R, Jaffee EM, Levitsky HI, Lazenby A, Leong K, Pardoll DM.; Dec. 1993
National Cancer Institute: Prostate Cancer Vaccine