Correlation of Ki-67 and gelsolin expression to clinical outcome in renal clear cell carcinoma

Objectives. To analyze the expression levels of Ki-67 and gelsolin in renal cell carcinoma (RCC) and determine their prognostic value in association with other clinicopathologic factors using tissue microarray technology. Histologic nuclear grade, performance status, and clinical stage are important prognostic factors in RCC. Because patients with tumors of similar grade, performance status, and stage may show a wide variation in biologic behavior and clinical outcome, additional biomarkers for RCC are needed to provide further prognostic information and possibly offer insight into the mechanisms of the disease. Methods. Using a renal cancer tissue microarray, we correlated the expression of Ki-67, a marker of cell proliferation, and gelsolin, an actin-binding protein, with grade, stage, and survival in patients with clear cell RCC. Results. In Cox multivariate regression analysis, stage (pT) was the most significant predictor of cancer-specific survival (P < 0.0001), followed by Ki-67 (P = 0.0216). In univariate analysis, increased Ki-67 expression predicted poor cancer-specific survival (P = 0.0006) when a cutoff value for Ki-67 staining was applied. In patients with grade 2 tumors, increased Ki-67 expression and decreased gelsolin expression in the same tumor was suggestive of poor cancer-specific survival (P = 0.0507). Conclusions. Our findings support the utility of Ki-67 as a prognostic biomarker for RCC and suggest a role for gelsolin in renal carcinogenesis. (C) 2003, Elsevier Science Inc.