Background: The presence of proliferating cell nuclear antigen (PCNA) has been suggested as a more important prognostic marker than either grade or mitotic index in the prognosis of patients with renal cell carcinoma. We assessed the immunoreactivity of PCNA in primary lesions and pulmonary metastases from patients with renal cell carcinoma and correlated the results with various histopathologic features and prognostic factors.
Methods: We studied the relationship between PCNA expression and clinical prognostic factors from resected primary lesions and pulmonary metastases from 10 patients and primary lesions from 32 patients with renal cell carcinoma without metastases. The cells were immunohistochemically stained with PCNA monoclonal antibody (PC-10) and 1000 nuclei were counted. The results were expressed as a ratio of stained to total cells (PCNA labeling index, LI %).
Results: The PCNA LI of pulmonary metastatic nuclei was significantly higher than the PCNA LI of renal lesions either from patients with (P < 0.05) or without (P < 0.01) metastases. Also, the mean PCNA LI of the pulmonary lesions in patients dying within 3 years of diagnosis was higher than the mean PCNA LI of patients surviving greater than 3 years.
Conclusion: Our findings suggest that the PCNA LI, which was determined by immunohistochemical analysis, is an important marker reflecting the biologic behavior of renal cell carcinomas. The degree of PCNA expression in this study was of prognostic significance.