Nervous system-specific enolase in serum as a marker for neuroblastoma.

Serum levels of nervous system-specific enolase (alpha gamma form plus gamma gamma form) were determined in 18 patients with neuroblastoma and in 40 control infants by means of a sandwich enzyme immunoassay method specific to the gamma subunit (or 14-3-2 protein) of enolase isozymes. Levels in patients with neuroblastoma were elevated (mean, 70.3; range, 6.2 to 330.0 ng/mL) when compared with those of control subjects (4.3 +/- 1.7 ng/mL). Most of the patients (6/7), whose serum nervous system-specific enolase level increased more than 100 ng/mL, died within 1 month. Serial measurements in patients with neuroblastoma receiving various therapies have revealed that there was a good correlation between serum nervous system-specific enolase levels and the course of the disease. These results indicate that the nervous system-specific enolase in serum may be a valuable marker for therapeutic monitoring of patients with neuroblastoma, as reported recently in patients with small-cell carcinoma of the lung.