Distribution of cytokeratins, vimentin and desmoplakins in normal renal tissue, renal cell carcinomas and oncocytoma as revealed by immunofluorescence microscopy.

Forty-two renal cell carcinomas, one oncocytoma and normal renal tissue were studied for the presence of cytokeratins and vimentin. The investigations were performed by immunofluorescence microscopy applying a panel of mono- and polyclonal antibodies to intermediate filament proteins. In all tumours except chromophobic renal cell carcinoma (CRCC) and oncocytoma a co-expression of cytokeratins and vimentin could be shown. The intermediate filament expression was often, however, very heterogeneous particularly with respect to the distribution of cytokeratins and vimentin, to the clonality of the antibodies used and to the tumour areas studied. The latter could be impressively demonstrated by examining a whole tumour. In CRCC and oncocytoma all tumour cells expressed cytokeratins and, in addition, single tumour cells also expressed vimentin. In normal renal tissue we could show vimentin-positive epithelia of proximal and distal tubules, which is reported for the first time.