[The clinical application of serum sialyl transferase determination as criterion of malignant transformation of cell surface structure (author's transl)].

The activity of a specific glycosyl transferase, namely, sialyl transferase was determined in a sera of patients with malignant disease. Increased serum sialyl transferase activity was observed in a high percentage of examined cases. The serum enzyme activity was also correlated to the clinical state of the patients and was found to depend on the tumor size. The enzyme activity decreased following surgical removal of the tumor mass and increased an appearance of metastases. These findings may be the basis for possible clinical application in the follow-up of patients with malignant disease, because the diagnostic value of serum sialyl transferase determination is greater than that of other serum analyses.