Immunocytochemical demonstration of neuron-specific enolase (NSE) in human lung cancers.

An anti-serum against human neuron-specific enolase (NSE), raised in sheep, has been characterized and used for immunocytochemical localization of NSE in paraffin sections of normal tissues and lung cancers. Of the small cell carcinomas (SCC), 69 out of 99 (70%) cases stained with the anti-serum. Maltreated biopsies showed a lower frequency of positive staining (19/39), indicating the importance of well-preserved biopsies. There was no clear difference in the staining between the oat cell and intermediate cell type of SCC. A majority (14 out of 21) of the non-SCC:s (large cell, adenocarcinoma and squamous cell carcinoma) were also stained by the anti-serum. Generally, this staining was weak and it could be blocked by preabsorption of the anti-serum by purified NSE. It is concluded that NSE expression, in conjunction with traditional histology, serves as a useful but not exclusive marker for SCC.