The use of a panel of monoclonal antibodies in ultrastructurally characterized small cell carcinomas of the lung.

In recent electron microscopic studies of 51 small cell carcinomas of the lung, the ultrastructural features of epithelial differentiation, particularly the presence of desmosomes, were associated with a tendency toward localized disease, clinical resectability and relatively long survival. Thirty-three of these cases were studied with a panel of monoclonal antibodies (B72.3, B1.1, AE1-AE3 and anti-Leu-7) directed against tumor-associated glycoprotein (TAG-72), carcinoembryonic antigen (CEA), cytokeratin and Leu-7 (an antigen common to natural killer cells and small cell lung carcinomas) to assess the correlation between the immunocytochemical and ultrastructural evidence of differentiation in tumors lacking differentiation at the light microscopic level. Of four small cell carcinomas with ultrastructural glandular differentiation, two were positive for CEA, three were positive for cytokeratin, and none were positive for TAG-72 and Leu-7. Of six tumors with ultrastructural squamous features, cytokeratin was expressed by three, CEA by one and TAG-72 and Leu-7 by none. Of the 23 classic oat cell carcinomas, cytokeratin was expressed by 14, Leu-7 by 3, CEA by 1 and TAG-72 by none. While the pattern of antigen expression did not predictably reflect the submicroscopic features, there was a significant association between keratin staining and extent of disease. The prospective use of similar antibody panels with both cellular and histologic material may therefore help to define clinically relevant categories of this biologically heterogeneous neoplasm.

Duke Scholars

Author John Daniel Shelburne Pathology