Objective: The aim of the study was to determine the prognostic power of Ki-67 immunostaining in renal cell carcinomas (RCC).
Methods: Clinical follow-up data were reviewed in 111 RCC and the results of Ki-67 immunolabelling were correlated to standard prognostic factors and survival data of the patients.
Results: Ki-67 expression correlated with tumor grade (p < 0.0001) and mitotic activity (p < 0.0001). In survival analysis Ki-67 expression could be used to divide patients into different prognostic groups (p = 0.0003). In separate analysis with M0 tumors Ki-67 immunolabelling was a powerful predictor of survival (p = 0.0016) as well as disease-free survival (DFS; p = 0.0067). In T1-2N0M0 tumors Ki-67 immunolabelling was superior (p = 0.0005) to other prognostic factors in survival analysis as well as in predicting DFS (p = 0.0006). Grade-2 tumors could be separated into distinct prognostic groups according to Ki-67 labelling (p = 0.0098). In Cox's multivariate analysis Ki-67 was an independent prognostic factor in all three subgroups of RCC.
Conclusions: The results show that Ki-67 expression is an independent prognostic factor in renal adenocarcinoma and could be applied in defining proper therapy for patients suffering from this malignancy.