Immunologic tests for the detection of gastrointestinal cancers: Status report on carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP)

Advances continue to be made in cancer detection by employing a variety of simple and sophisticated serum assays for tumor antigens. Whether or not these antigens are tumor specific may not be as important a consideration as that they are usually tumor associated. Certain clinical circumstances may result in seropositivity in the absence of tumor. The clinician should be aware of these circumstances so that he can assign accurate significance to seropositivity. In addition to usefulness of such assays in cancer detection and assessment of therapeutic responsiveness, serodiagnosis has paved the way for enhanced understanding of tumor immunogenesis and possible immunotherapy.