We have largely completed one stage of our studies by demonstrating (1) the nonspecificity of CEA and (2) its clinical usefulness in numerous digestive tract diseases. We are continuing the study of the diagnostic and prognostic use of prospective sequential tests of immune status in our patients with benign and malignant gastrointestinal diseases. These clinical studies include patients with colonic, pancreatic and qastric cancer, both before and after resection, premalignant states such as polyps, gastric atrophy and ulcerative colitis and other disorders such as cirrhosis and pancreatitis. We are assessing and improving available assay systems and investigating methods for preparing new human tumor antigens. In addition, we are presently investigating tests of cell-mediated immunity. Prospective sequential evaluation of individual patients is being studied. Our studies show that CEA measurements reflect (and may predict) clinical prognosis; but not in all instances. We are studying further (a) CEA and other tumor "markers" in order to improve this performance, and (b) other indicators of the patient's immune status including those which reflect reactivity to his own cancer; (c) the histology of the patient's tumor. An immunologic cancer profile is thus defined. Preliminary studies suggest that simultaneous measurements of CEA levels, tumor antigen induced inhibition of mononuclear cell migration, selected skin tests of delayed hypersensitivity, and tumor histology may yield useful patterns of response.