While it is statistically true that clinical cancer occasionally occurs following development of immune incompetency, the fact remains that the most common forms of cancer (ie, breast, lung, and colon) are not experienced by immunosuppressed individuals. Since there is strong scientific evidence that the unprovoked, normal immune system does not recognize and destroy cancer cells that arise spontaneously, the concept of an immune surveillance system that continuously protects clinically normal humans from cancer remains an appealing but unproven hypothesis. Burton's theory of immune surveillance against cancer appears to be nothing more than a rehash of the hypotheses of many other investigators, embellished with his postulate that four specific anticancer protein factors exist and function in the normal human immune system. The IAT he invented as a treatment for cancer is based on his presumption that he has proven the existence of these factors. But neither his declarations nor those of his proponents offer any objective evidence to support such a conclusion. They have not proven that the IAT components exist or can be extracted from blood without the loss of biologic activity. The tests that are described cannot quantitatively measure the specific IAT proteins and there is no evidence that the IAT fractions possess any immunologic activity. Thus, Burton's tumor antibody has never been shown to be a tumor specific immunoglobulin that can interact with tumor antigens and activate complement. His tumor complement fraction has no complement activity (written communication, G.J. Gray, PhD, June 21, 1984), his blocking protein has not been shown to block anything, his deblocking protein has not been shown to deblock anything, and his human tumor cells have never been shown to lyse following the interaction of tumor antibody and tumor complement. Finally, since there is no information on the quality control procedures being used in the manufacture of the IAT materials, there is the possibility that they may be unsterile and, therefore, hazardous for use in humans. Patients who are considering IAT as treatment for cancer should be made aware of these facts when attempting to reach an informed decision regarding its safety and potential efficacy. While this paper was being reviewed for publication, an IAT proponent newsletter called The Cancer Chronicles published the news that Lawrence Burton died of a heart attack in March 1993. The editor of this newsletter, Ralph Moss, PhD, stated that Burton's clinic would remain open under the direction of its medical director, R. John Clement, MD, and would continue to offer IAT to cancer patients.(ABSTRACT TRUNCATED AT 400 WORDS)