Prognostic and clinicopathological role of high Ki-67 expression in patients with renal cell carcinoma: a systematic review and meta-analysis

Previous studies have elevated the prognostic value of Ki-67 in renal cell carcinoma (RCC), but the reports are controversial and inconsistent. We conducted a systematic review and meta-analysis to clarify the significance of Ki-67 in RCC prognosis. We systematically searched PubMed, Web of Science, and Embase to identify relevant studies until April 2016. Based on the inclusion and exclusion criteria, 20 studies, including 5,398 patients, were eligible for further analysis. Results showed that high Ki-67 expression in RCC was associated with poor OS (HR = 1.95, 95% CI: 1.44-2.64), CSS (HR = 1.67, 95% CI: 1.47-1.89), and DFS (HR = 2.56, 95% CI: 1.79-3.67). In addition, high Ki-67 expression was significantly associated with TNM stage (III/IV vs. I/II: RR = 2.03, 95% CI: 1.68-2.44), pathological T stage (T3/T4 vs. T1/T2: RR = 1.67, 95% CI: 1.35-2.06), metastasis (yes vs. no: RR = 2.15 ,95% CI: 1.77-2.62), and Fuhrman grade (III/IV vs. I/II: RR = 1.77, 95% CI: 1.20-2.60). Our study suggested that Ki-67 was a prognostic marker in RCC. High Ki-67 expression was correlated with poor prognosis and advanced clinicopathological features, and it could serve as a biomarker for disease management.