Dual Immunologic Property of S-100 Protein in Normal Eyes and Eyes with Retinoblastoma: A Histopathological and Immunohistochemical Study of 88 Cases

Abstract

To ascertain the cell types expressing S-100 protein in eyes with retinoblastoma, a follow-up study was made on 88 formalin-fixed and paraffin-embedded retinoblastoma specimens histopathologically and immunohistochemically, using antibodies against S-100 protein. In normal retinas and morphologically normal retinas with retinoblastoma, both astrocytes and ganglion cells were stained positively for S-100 protein. In the retinoblastomas, not only the reactive astrocytes in most cases, but also large tumor cells with large cell bodies, prominent nucleoli and well-differentiated figures were positive for S-100 proteins in 2 cases. These large tumor cells were thought to be neuronal and were called ganglion-like cells because they were morphologically and immunohistochemically compatible with the large ganglion cells in normal retina. The results indicate that in eyes with retinoblastoma, S-100 protein has both neuronal and glial immunologic properties and could have a limited value as a glial marker for the histogenesis study of retinoblastoma.