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Researchers Hopeful About Breast Cancer Vaccine (dateline March 28, 2000)


A new study presented at the Advances in Human Breast and Prostate Cancer symposium in Lake Tahoe, Nevada revealed that certain proteins found on the surface of breast cancer cells could possibly be used to develop a vaccine against the disease. According to the researchers, a significant number of breast cancer patients express these proteins (called antigens) and could benefit from a vaccine. Eventually, researchers may be able to use antigen identification to help screen for and detect breast cancer.

Lead researcher Patrick C. Roche, PhD of the Mayo Clinic in Rochester, Minnesota believes his study could hold promise for breast cancer patients, particularly women with advanced breast cancer and those who do not respond well to chemotherapy. In the study, 217 breast cancer tissue samples were analyzed for certain cancer/testin (C/T) antigens: ESO-1, MAGE-1, and MAGE-3.

Though these antigens may be found in healthy tissues, they have also been identified in several cancer tissues, including melanoma and esophageal cancer. The results of the study revealed that at least one of the antigens was present in nearly 90% of the breast cancer samples. All three antigens were found in 29% of the breast cancer tissue samples.

Immunotherapy, which involves treating a disease by enhancing an immune response, has not received much attention as a possible breast cancer treatment, according to Dr. Roche, since chemotherapy has become an accepted treatment. However, some patients do not respond well to chemotherapy (or experience harsh side effects) and may benefit from a vaccine treatment.

Though the study is promising, at the moment, the idea for a breast cancer vaccine is theoretical and could take 10 years or longer to fully develop. Extensive research is still needed before a vaccine can be created, and at that point, the vaccine must be tested multiple times in studies with animals and eventually humans. Though they are only at the start of their investigation, the researchers are optimistic. Paul Lindholm, MD of the Medical College of Wisconsin in Milwaukee says there may indeed be "a future prospect of immunotherapy [for breast cancer]."

For some time, researchers have been trying to develop a vaccine that involves using the MAGE (melanoma antigen) in patients with melanoma, a type of skin cancer. Vaccines work by introducing the body to specific antigens (the same antigens that are present in the diseased cells). When the vaccine is injected, the immune system recognizes that these antigens are foreign substances and alerts its own cells (T-cells). T-cells then attack the cancer cells because they now recognize foreign substances in them. Without a vaccine, the immune system does not recognize that the antigens on the cancer cells are foreign and will not launch an attack.