Immunologic tests in diagnosis of cancer.

A variety of immunologic approaches may be potentially useful for the immunodiagnosis of cancer. These sensitive procedures might assist in the initial detection, diagnosis, and localization of tumors, and might also be used in determining prognosis and for monitoring cancer patients for recurrence of disease after therapy. The types of approaches and some of the available information regarding their clinical usefulness are reviewed. The main emphasis with potential immunodiagnostic tests has been placed on detection of circulating tumor-associated markers. However, the detection of tumor markers in tissue cells might help in the discrimination between tumor cells and nonneoplastic cells, and also might help in the categorization of the type of cancer. Detection of depressed immunologic competence or in a subpopulation of lymphoid cells may be useful in diagnosis. Humoral or cell-mediated immune responses to tumor-associated antigens have the potential of being very sensitive, specific indicators of neoplastic disease, but most of the tests for these responses are difficult and none has yet been established for use in practical clinical situations.