Expression of the human nephron differentiation molecules in renal cell carcinomas.

The authors tested frozen sections from 28 renal cell carcinomas (RCC)--21 clear, 1 eosinophilic, 4 basophilic, and 2 spindle-shaped cell type--with monoclonal antibodies (MAb) reacting against cytokeratin, vimentin, CD24, CALLA/CD10, villin, CD26, and HLA class I and class II molecules. These molecules are markers of specific segments of the mature kidney, and their loss or acquisition reflects the different steps of human nephrogenesis. KI67 MAb was used to evaluate cell-proliferating activity.