A monoclonal antibody against neuron-specific enolase. Immunohistochemical comparison with a polyclonal antiserum.

There is skepticism about the value of antisera to neuron-specific enolase (NSE) for immunohistochemical identification of neural and neuroendocrine differentiation in neoplasms, because of reports of detection of NSE, in a large percentage of nonneuroendocrine neoplasms. By immunohistochemical methods, the authors compared a monoclonal antibody to NSE (Mab NSE) with a heterologous antiserum to NSE (Het NSE) on 348 samples of tumors of diverse histogenesis. They studied 93 neural and neuroendocrine tumors and 255 nonneuroendocrine, nonneural tumors. The Mab NSE was slightly less sensitive but clearly more specific than the Het NSE in recognizing neural and neuroendocrine differentiation. Only 2% of the nonneuroendocrine, nonneural tumors reacted positively with Mab NSE; in contrast, 20% of the same tumors were positive with the Het NSE. Moreover, intense nonspecific staining was frequent with Het NSE, which often rendered interpretation difficult. Because of its superior specificity, the Mab NSE used in this study is more valuable than the heterologous antiserum as a diagnostic reagent in tumor diagnosis.