[Serum neuron-specific enolase as a marker of lung cancers]

Neuron-specific enolase (NSE) in sera of lung cancer patients was studied in order to evaluate its clinical significance as a tumor marker. The subjects included 15 normal volunteers, 13 cases without malignant neoplasms or neuronal diseases and 42 lung cancer cases. NSE was quantified by a double antibody radioimmunoassay. As one of the sera from normal volunteers and control patients showed an NSE content 10 ng/ml or more, values of 10 ng/ml or over were considered to be positive. Seventeen of 42 sera from lung cancer patients showed positive NSE levels. Histological evaluation revealed that the degrees of NSE positiveness for small cell carcinoma, large cell carcinoma, squamous cell carcinoma and adenocarcinoma were 73%, 50%, 33%, and 21%, respectively, and that all the positive cases except for one were confined to disease stages III or IV. The level of NSE in patients with 10 ng/ml or more before surgery decreased to within normal limits 1-2 weeks after surgery Localization of NSE could be confirmed immunohistologically in small cell carcinoma cells. In conclusion, NSE was considered to be very useful as a tumor marker of the lung, especially in small cell carcinoma for diagnosis and determination of disease extent and response to therapy, and also in non-small cell carcinoma for the evaluation of treatment effectiveness.