The role of monoclonal antibodies in brain tumour diagnosis and cerebrospinal fluid (CSF) cytology.

This paper reviews the diagnostic role of monoclonal antibody immunohistochemistry in a series of 189 brain tumour biopsies and 22 cases of neoplastic meningitis. The diagnostic monoclonal antibody panel, which includes markers for glial, neural, epithelial and lymphoid differentiation antigens, was used to test a wide variety of cerebral and spinal tumours by indirect immunofluorescence and immunoperoxidase techniques on unfixed frozen sections. Gliomas, meningiomas, schwannomas, medulloblastomas, choroid plexus tumours, cerebral lymphomas and metastatic carcinomas could all be reliably differentiated by means of their characteristic antigenics profiles, as defined by their patterns of reactivity with the antibody panel. Confident diagnosis was possible even in very poorly differentiated tumours and in biopsies distorted by surgical squeeze artefact, where paucity of morphological clues made diagnosis by conventional histological methods difficult or impossible. It was estimated that use of the antibody panel was responsible for, or made a significant contribution towards the final diagnosis in approximately 20% of cases. The monoclonal reagents were also found to be of great value in the detection and characterisation of neoplastic cells in CSF specimens from patients with malignant meningitis. Malignant cells were detected in 73% of cases and characterised in 16% of cases by routine cytological techniques. Employing monoclonal immunocytology however, these figures were improved to 95% and 95% respectively. Our findings suggest that patients with neoplastic meningitis can be spared prolonged investigation and inappropriate management by the early detection and characterisation of malignant cells in CSF using panels of monoclonal antibodies.