“…On the other hand, meningitis which preserves neuronal tissue, showed no change in NSE levels [4]. The gamma-gamma isoenzyme in plasma is also important in the diagnosis of tumours originating from APUD-cells, like neuroblastoma, melanoma, retinoblastoma, small cell carcinoma of the lung and certain carcinomas of the thyroid, the pancreas and the gut, although the specificity for these tumours is in discussion in the literature [6-121. Enzyme-immunoassays [4,13] and radioimmunoassays [3,5,11,12,14] have been employed to measure gamma-gamma enolase. Gerbitz was the first to use a bioluminescence technique for the measurement of NSE in human plasma [15].…”