Expression of segment-specific antigens in the human nephron and in renal epithelial tumors.

The immunohistological staining patterns of several hundred monoclonal antibodies (Mabs) were studied in normal human kidney tissue. Seven Mabs, 3 hematopoietic (F103.12/CD10, MY7/CD13, 3C4/CD15) and 4 non-hematopoietic (LP34, E29, HEA81, HEA125) revealed a segment-specific or pan-nephron staining. The expression of antigens (Ags) labelled by the 7 selected Mabs was then studied in cryostat sections of a series of 43 renal epithelial tumors (31 renal cell carcinomas, 2 oncocytomas, 10 adenomas) in order to correlate the results with the prevailing hypothesis for the histogenesis of these tumors. The adenomas displayed poor expression of CD10-Ag (proximal nephron marker) compared to carcinomas. The chromophobic type of renal cell carcinoma and the benign oncocytoma did not express CD13-Ag, suggesting a possible histogenetic relationship. More than 95% of all tumors simultaneously expressed a proximal and a distal marker. Our results suggest that CD10-antibody may be of value in the distinction between benign and malignant small-sized renal tumors. We conclude that neoplastic transformation may imply such alterations in the expression of marker-Ags (proximal/distal) that no conclusion can be drawn regarding the tubular segment from which a renal epithelial tumor takes its origin.