POLYSIALYLATED NEURAL CELL-ADHESION MOLECULE AS A MARKER FOR DIFFERENTIAL-DIAGNOSIS IN PEDIATRIC TUMORS

Background/Purpose: Some malignant pediatric tumors express the polysi alylated form of the neural cell adhesion molecule (PSA-NCAM), which n ormally becomes restricted to a few regions of neural plasticity and r egenerating nerve tissue after embryogenesis. Recently, serum concentr ations of polysialylated NCAM have been shown to be tumor associated i n children with rhabdomyosarcoma and neuroblastoma. This study was und ertaken to evaluate polysialylated NCAM as a marker helpful in disting uishing between various embryonal tumors and other lesions suspicious of a malignancy. Methods: Fresh frozen specimens from exemplary tumors of the thorax, adrenal glands, and kidneys of 17 children were invest igated immunohistochemically by the Alkaline Phosphatase anti-Alkaline Phosphatase (APAAP) technique. Simultaneously, the patients' serum wa s investigated by a chemiluminescent immunoassay, which likewise used the polysialic acid-specific monoclonal antibody 735. Results: Serum c oncentrations correlated with the expression of PSA-NCAM in immunohist ochemistry. They were elevated in children with PSA-NCAM-positive tumo rs as alveolar rhabdomyosarcoma, undifferentiated neuroblastoma, and a naplastic Wilms tumor, but negative in all other patients. Conclusion: PSA-NCAM serves as a useful marker for differential diagnosis during workup of tumors suspicious of a malignant neoplasm. Copyright (C) 199 8 by W.B. Saunders Company.