Does the Immunophenotype of Renal Cell Carcinoma Correlate with Its Clinical Stage

The following comparative study is an analysis of the clinical data, morphology and immunophenotype of 93 patients who have been operated on for renal cell carcinoma. We were able to show a close link between the histological grade and the occurrence of distant metastases: 33% of the patients with grade III tumours versus 11.5% of the patients with grade I tumours had developed metastasis by the time of the surgery. Histological subtyping per se did not give prognostic hints. Immunohistochemistry has revealed an inconsistent reaction pattern for the cytokeratin marker K11 (18/22). For proper diagnosis a panel of cytokeratin markers should be employed. The reaction patterns of monoclonal antibodies against the epidermal growth factor receptor (EGFR) and against myelomonocytic antigens in normal renal tissue (positive for the tubulus system) and in renal carcinoma indicate that renal cell carcinoma derive from the tubulus system. The proliferation marker Ki-67 correlates well with the histological grading. Although only a limited number of snap-frozen tumours have been investigated, this study indicates that EGFR is expressed by normal and by malignant renal tissue and that Ki-67 may serve as a prognostic marker.