New research shows that the type of immunosuppresive drug that organ transplant patients receive could have a direct influence on their chances of developing cancer. According to scientists at the University of Regensburg, Germany, the newer immunosuppressive drug, rapamycin may reduce the risk of subsequent tumor development, whereas older drugs such as cyclosporine could facilitate cancer growth.
Following organ transplantation, patients are treated for prolonged periods of time with drugs that suppress their immune systems to try and prevent them from rejecting the transplanted tissue. One serious consequence of this treatment is the increased tendency to develop either new or recurring cancers. Some studies suggest that transplant patients receiving immunosuppressive drugs have a 20-500 fold higher incidence of certain types of cancer.
With this in mind, Edward Geissler and colleagues at the University of Regensburg tested the effects of two immunosuppressive drugs in a mouse model of liver metastasis from colon cancer (Nature Medicine, Vol. 8, No. 2, p. 128, 01 Feb 02). They found that mice treated with the immunosuppressant rapamycin had a reduced presence of tumor in the liver, whereas those treated with cyclosporine showed the converse - an increased amount of liver cancer. The scientists believe that rapamycin prevents the development of cancer by blocking angiogenesis (the formation of new blood vessels).
Dr. Edward K. Geissler
Department of Surgery
University of Regensburg
(C) Nature Medicine press release.
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