Sialic acid as a marker for differentiation between benign and malignant intracranial tumors.

One of the characteristics of malignant tumor cells is the production of glycocompounds with a high content of N-acetylneuraminic acid (sialic acid). Total sialic acid concentration was determined in the serum of 136 patients with an intracranial tumor. The concentration was determined enzymatically and using HPLC. Both methods had a relatively high specificity (90%), provided an inflammatory process due to an infection could be excluded. Sensitivity was 72.6%; the cut-off level of sialic acid concentration was determined to be 2.75 mumol/ml. There was a significant difference in the average sialic acid concentration of benign and malignant tumors. The test was least reliable in determining whether the growth of an astrocytoma is malignant.