NEUN - A USEFUL NEURONAL MARKER FOR DIAGNOSTIC HISTOPATHOLOGY

The monodonal antibody A60 specifically recognizes the DNA-binding, ne uron-specific protein NeuN, which is present in most neuronal cell. ty pes of vertebrates. In this study we demonstrate the potential use of NeuN as a diagnostic neuronal marker using a wide range of formalin-fi xed, paraffin-embedded human surgical and autopsy specimens from the c entral and peripheral nervous system, After microwave antigen retrieva l, almost all neuronal populations revealed strong immunoreactivity fo r NeuN in nuclei, perikarya, and some proximal neuronal processes, whe reas more distal axon cylinders and dendritic ramifications were not s tained. The stain greatly enhanced the gray matter architecture. NeuN immunoreactivity was not detected in Purkinje cells, most neurons of t he internal nuclear layer of the retina, and in sympathetic chain gang lia. We examined nine gangliogliomas and 14 dysembryoplastic neuroepit helial tumors, one ganglioneuroma, and one dysplastic cerebellar gangl iocytoma. The neuronal component of all of these lesions showed marked immunoreactivity for NeuN. In addition, NeuN immunoreactivity was foc ally seen in one of seven medulloblastomas with prominent neuronal dif ferentiation. There was no staining of non-neuronal structures. The re sults indicate that NeuN immunoreactivity is a sensitive and specific neuronal marker in formalin-fixed, paraffin-embedded tissues, and may be useful in diagnostic histopathology.