Immunohistochemical study of neuroblastoma and related tumors with anti-S-100 protein antibody.

Histological sections of 36 cases of neuroblastoma and related tumors were studied with anti-S-100 protein antibody (PAP method). Schwann cells in the ganglioneuromas and ganglioneuroblastomas always strongly stained. In addition, varying numbers of spindle-shaped or elongated positively staining cells, which were probably Schwann cells and their precursor cells, were demonstrated in ganglioneuroblastoma and differentiating neuroblastoma. Undifferentiated round cell neuroblastoma showed no reaction. Immunohistochemical findings of these cases were classified into four groups (+ +, +, +/-, -) according to the number of the positive cells and compared with prognosis, histological typing, location of the tumors, stage, and age at surgery. The cases with many positive cells, group (+ +) showed excellent prognosis, and group (-) showed very poor prognosis. The results of this study indicate that S-100 protein staining provides a reliable objective method for evaluation of differentiation of the neuroblastoma cells toward Schwann cells, which appears to be an important factor to predict prognosis.