Enolase isozymes as markers for differential diagnosis of neuroblastoma, rhabdomyosarcoma, and Wilms' tumor.

Enolase isozymes (alpha, beta and gamma enolases) in the extracts of pediatric tumors (neuroblastoma, ganglioneuroblastoma, rhabdomyosarcoma and Wilms' tumor) were determined by means of enzyme immunoassay systems. All tumor tissues examined contained alpha enolase at high levels (2070-19100 ng/mg protein). The beta and gamma enolases were present at high levels particularly in rhabdomyosarcoma (886 +/- 750 ng/mg protein) and (ganglio)neuroblastoma (2060 +/- 890 ng/mg protein), respectively. Immunohistochemical studies confirmed these results. Serum levels of these enolase isozymes were also determined in pediatric tumor patients. Before treatment, a serum sample from a patient with rhabdomyosarcoma contained a high level of beta enolase and serum samples from patients with (ganglio)neuroblastoma contained high levels of gamma enolase. However, the levels of serum beta and gamma enolases were low in patients with Wilms' tumor. The elevated level of beta or gamma enolase in serum from rhabdomyosarcoma or (ganglio)neuroblastoma patients was markedly decreased after adequate treatment (operation, chemotherapy or radiation). The results indicated that the enolase isozymes are useful marker antigens for differential diagnosis and therapeutic monitoring of neuroblastoma and rhabdomyosarcoma.