Prognostic value of cyclin E expression in breast cancer: a meta-analysis

Cyclin E is an important regulator of cell cycle progression. Various studies examined the relationship between cyclin E overexpression with the clinical outcome in patients with breast cancer but yielded conflicting results. Electronic databases updated to May 2013 were searched to find relevant studies. A meta-analysis was conducted with eligible studies which quantitatively evaluated the relationship between cyclin E overexpression and survival of patients with breast cancer. Survival data were aggregated and quantitatively analyzed. We conducted a final analysis of 7,759 patients from 23 eligible studies and evaluated the correlation between cyclin E overexpression and survival in patients with breast cancer. Combined hazard ratios suggested that cyclin E overexpression had an unfavorable impact on overall survival (OS) (hazard ratio (HR) = 1.30, 95 % confidence interval (CI), 1.12-1.49) and breast cancer-specific survival (BCSS) (HR = 1.48, 95 % CI, 1.03-1.93), but not disease-free survival (HR = 1.11; 95 % CI, 0.96-1.27) in patients with breast cancer. Significantly, risks were found among stage I-II breast cancer for (HR = 1.75; 95 % CI, 1.30-2.19). Cyclin E overexpression is associated with poor OS and BCSS in breast cancer.