[Tumor markers as a means of cancer diagnosis--expectations and problems]

The number of tumor markers used clinically has grown rapidly in recent years. The applicability of these substances to the improvement of cancer diagnosis is reviewed. The practical utility of most of the available markers is severely limited by their insufficient specificity and sensitivity. It is emphasized that, at present, the early diagnosis of common tumors by means of screening with specific markers is practically impossible. The suitable markers rather promise to be useful in the postoperative care of cancer patients, especially with respect to the estimation of the therapeutical success, the risk of metastatic processes, and the prognosis. The recently introduced monoclonal antibodies may assist in reaching a higher level of diagnostic statements. The markers CA 12-5, CA 15-3, CA 19-9, CA 50, TPA, and Neopterin are considered in detail.