preventing a viral infection. Nevertheless, encouraging results have been obtained in melanoma, colon, ovarian, breast and kidney cancers and in lymphomas.
Although vaccines alone have not been effective in more than 20 percent of patients with melanoma or kidney cancer, higher response rates have been suggested when vaccines are used in combination with other agents such as interferons and interleukins .
The National Cancer Institute in the U.S. has made tumor vaccines a priority area of research, so this type of immunotherapy will receive a great deal of attention over the next decade, specifically with altered tumor cells and purified tumor antigens .
Tumor Necrosis Factors (TNFs) Tumor necrosis factors alpha and beta (also called lymphotoxins) are cytokines produced by both macrophages and lymphocytes . TNFs can stimulate immune cells, damage tumor cells directly, influence the blood vessels around tumors and make tumors more recognizable to the immune system .
Unfortunately, high doses of TNFs are very toxic and have not been useful against tumors. Smaller doses or doses administered at the tumor site may prove to be beneficial in combination with other treatments.
