PROLIFERATING CELL NUCLEAR ANTIGEN AND MIB-1 - AN ALTERNATIVE TO CLASSIC PROGNOSTIC INDICATORS IN RENAL-CELL CARCINOMAS

Tumor progression and clinical outcome for patients with renal cell ca rcinomas (RCCs) cannot be predicted based solely on tumor staging and grading. In a retrospective study we have therefore attempted to analy ze the capacity of proliferation markers to provide additional prognos tic information. One hundred seven cases of RCC were investigated by i mmunohistochemical analysis using two different monoclonal antibodies: PC10, which recognizes a proliferating cell nuclear antigen (PCNA), a nd MIB-1, which identifies the Ki-67 antigen in formalin-fixed, paraff in-embedded material. PCNA frequency ranged from 0% to 71% (mean, 17%) , and MIB-1 expression, from 0% to 43% (mean, 11%). PCNA scores correl ated significantly with MIB-1 immunoreactivity. PCNA and MIB-1 immunor eactivity showed a significant correlation with tumor grade. A strong correlation was also observed for T-component of stage and MIB-1 score s, but no correlation was found between PCNA and T-component of stage. In univariate analysis, PCNA immunoreactivity and MIB-1 scores were s ignificant predictors of survival. Multivariate analysis, using a Cox proportional hazard model, showed PCNA index, N-component of stage, an d tumor grade to be independent predictors of tumor progression, which is not the case for MIB-1 index.