Ki-67 is a Valuable Prognostic Factor in Gliomas: Evidence from a Systematic Review and Meta-analysis

Ki-67 has been widely used as an indicator of cell proliferation in gliomas. However, the role of Ki-67 as aprognostic marker is still undefined. Thus, we conducted a meta-analysis of the published literatures in order toclarify the impact of Ki-67 on survival in glioma cases. Eligible studies were identified in PubMed, EMBASE, ISIWeb of Science, Cochrane Central Register of Controlled Trials, Science Direct and Wiley Online Library withthe last search updated on August 31, 2014. The clinical characteristics, overall survival (OS) and progressionfreesurvival (PFS) together with Ki-67 expression at different time points were extracted. A total of 51 studies,covering 4,307 patients, were included in the current meta-analysis. The results showed that overexpression ofKi-67 can predict poor OS (HR=1.66, 95%CI: 1.53-1.80; Z=11.87; p=0.000) and poor PFS (HR=1.67, 95%CI:1.47-1.91; Z=7.67; p=0.000) in gliomas. Moreover, subgroup analyses also indicated that high level of Ki-67expression was related to poor OS and PFS in glioma patients regardless of region, pathology type, cut-offvalue and statistical method. In conclusion, the current meta-analysis revealed that Ki-67 expression might bea predicative factor for poor prognosis of glioma patients, emphasizing its importance as a predictor.