Anti-neuronal nuclear autoantibodies, types 1 and 2: their utility in the study of tumors of the nervous system.

This is a comprehensive immunohistochemical study of selected archival tumors of the nervous system applying human anti-neuronal nuclear autoantibodies of types 1 and 2 (ANNA-1 and -2), serum markers of paraneoplastic syndromes associated primarily with small cell lung cancer (SCLC). Neither ANNA-1 nor ANNA-2 bound to glial tumors regardless of histological grade and subtype; instead they labeled neurons in overrun normal parenchyma. Central neurocytomas and the neuronal components of mixed glioneuronal tumors were also immunoreactive for both. In addition, varying proportions of tumor cells were stained in dysembryoplastic neuroepithelial tumor, subependymal giant cell astrocytoma (SEGA), tuber and neuroblastoma. All other tumors were nonreactive, namely choroid plexus papilloma, pituitary adenoma, pineocytoma, pheochromocytoma, thymic and pulmonary carcinoid, chordoma, meningioma, schwannoma and metastatic melanoma. SCLC was immunonegative for ANNA-1 and ANNA-2 in paraffin preparations, but displayed strong immunoreactivity for both in frozen sections: this discrepancy was not observed in other tumors studied. In conclusion, the human IgG autoantibodies ANNA-1 and ANNA-2 provide novel tools for studying the cytogenesis of tumors of the nervous system in that they permit the identification of both normal and neoplastic, poorly differentiated and small neuronal cells that may escape detection using commercially available anti-neuronal antibodies.