What is responsible for the development of cachexia?
For a long time, scientists believed that cancer would soak up all the incoming nutrients to fuel its own growth and thereby starve the rest of the body. This theory proved to be unlikely, however. Even small tumors, that comprise less than five percent of the patients weight, can cause cachexia. Furthermore, cachexia can be seen in cancer patients receiving excess calories intravenously. Early experiments using mice and rats showed that one can create a cachetic state in healthy animals by transfusing them with large amounts of blood from an animal with cancer cachexia. With cessation of transfusions, the healthy animal’s cachexia resolves. When cancer stricken animals were operated on and the tumor was surgically excised, the animal gained weight. Such animal work has made clear, that there must be certain blood circulating substances produced the tumor itself that are responsible for the cachexia. Recent data proved these substances are cytokines, such as tumor necrosis factor alpha
