Neuron-specific enolase concentrations in serum in benign liver diseases

Neuron-specific enolase (EC 4.2.1.11; NSE), a glycolytic enzyme produced by neuronal and neuroendocrine cells, is used as a tumor marker of neuroendocrine cancers, especially small-cell lung cancer. We have evaluated the behavior of NSE in nonmalignant liver diseases in 161 patients who underwent a thorough clinical and biochemical evaluation. Nine of the 161 patients (5.6%)--three of the 86 cirrhotic patients (3.5%), and six of the 75 noncirrhotics (8%)--had abnormal concentrations of NSE. Of the numerous clinical and analytical factors considered, none correlated significantly with NSE. The low false-positive rate, similar to or even lower than for other benign diseases, and the absence of association with the numerous characteristics of liver diseases that we studied, support the lack of any substantial metabolism of NSE by the liver. Consequently, the coexistence of a benign liver disease does not limit the usefulness of this enzyme as a tumor marker.