An immunocytochemical demonstration of calcineurin in human nerve cell tumors. A comparison with neuron-specific enolase and glial fibrillary acidic protein.

Human central and peripheral nerve cell tumors were examined in detail using antibodies to calcineurin, glial fibrillary acidic protein (GFAP) and neuron-specific enolase (NSE). Forty-eight formalin-fixed and paraffin-embedded specimens of human neuronal tumors, including 27 medulloblastomas, were examined. Calcineurin-positive cells were found in all peripheral nerve cell tumors and the two gangliogliomas, whereas 20 of the 27 medulloblastomas and one of the two cerebral neuroblastomas did not contain calcineurin-positive cells. Differentiation of cells along the neuronal lines was positively correlated with calcineurin immunoreactivity. NSE-positive cells were found in all of the tumors with the exception of the one cerebral neuroblastoma. NSE immunoreactivity was not invariably consistent with calcineurin immunoreactivity and non-neuronal cells were often positive. Calcineurin-positive cells were all devoid of GFAP, but NSE-positive cells expressed GFAP in some tumors. GFAP-immunoreactive cells were found only in central nerve cell tumors, and not in peripheral tumors. In addition, GFAP-positive cells in some tumors such as retinoblastoma and medulloblastoma morphologically revealed not only neoplastic but also reactive astrocytic features.