Neuron specific enolase (NSE) and thymidine kinase (TK) as markers in biological fluids of brain tumor patients.

We studied the activity of two enzymes NSE and TK in the biological fluids of 104 patients with nervous system diseases, who fell into 4 groups. 20 subjects out of 35 in the tumor group had glial tumors. We fixed a cut-off value of NSE and TK activity at the 95th percentile of the control group, both in serum and in CSF. The aim of our investigation was to assess the reliability of TK and NSE assays in separating brain tumors from other neurological diseases. In our patients, most of the TK activity above the cut-off value was found in the tumor group. Serum TK seems to be a useful marker for following up cerebral tumors after surgery, but NSE is less useful for this purpose.