An immunohistochemical study on the distribution of glial fibrillary acidic protein, S-100 protein, neuron-specific enolase, and neurofilament in medulloblastomas.

In order to clarify the differentiation of medulloblastomas, the authors studied on the morphological features and immunohistochemical expression of glial fibrillary acidic protein (GFAP), S-100 protein, neuron-specific enolase (NSE), and neurofilament (NF) in 31 medulloblastomas. GFAP was detected only in a small number of tumor cells of 5 medulloblastomas; S-100 protein in both small tumor cells and some so-called spongioblastic cells in 16 medulloblastomas; NSE in the more abundant tumor cells and the matrix in 28 medulloblastomas; NF in a few tumor cells of 12 medulloblastomas; GFAP and NF in 2 medulloblastomas, but each of them in different tumor cells. These results suggest that medulloblastomas have a capacity of differentiation along neuronal and/or glial lines. The conventional morphological markers of differentiation in medulloblastomas such as spongioblastic cells and Homer Wright rosettes were not necessarily compatible with expression of immunohistochemical markers such as GFAP or NF. NSE and S-100 protein seem less valuable markers of differentiation because they were detected in both neuronal and glial elements. But NSE, which was observed in most medulloblastomas, might have a value as a marker for medulloblastomas.