Tumor immunology and its application to the diagnosis of cancer.

There are several types of immunological approaches to the diagnosis of cancer. The search for circulating tumor associated antigens has been used most extensively. Carcinoembryonic antigen (C EA ) and alpha-fetoprotein are the best studied examples. In addition, several hormones and other proteins have shown some association with the neoplastic state. Other immunodiagnostic approaches include the study of the general immune competence of cancer patients and the cell-mediated and humoral immune response to tumor associated antigens. Although several assays seem promising, none have been adequately evaluated as to their sensitivity and specificity. The potential role of these tests in screening for cancer, in differential diagnosis and in monitor­ ing of the cancer patient after therapy remains to be determined.