The impact of cyclin D1 overexpression on the prognosis of bladder cancer: a meta-analysis

BACKGROUND: To evaluate the relationship between cyclin D1 overexpression and bladder cancer prognosis. METHODS: A systematic literature search up to July 27, 2013 was carried out in PubMed and Wanfang databases, and the references of retrieved articles were screened. The hazard ratios (HRs) and their 95% CIs were used to combine the data. Heterogeneity and publication bias were also evaluated. RESULTS: A total of 15 studies containing 2,591 cases were included. We found that increased cyclin D1 levels were significantly correlated with progression-free survival with a pooled HR estimate of 0.54 (95% CI: 0.32–0.92). There was a significant degree of heterogeneity (I(2) = 93.8%, P <0.001). Moreover, subgroup analysis indicated that elevated cyclin D1 levels were significantly associated with overall survival in muscle-invasive bladder patients (HR: 0.95, 95% CI: 0.91–0.99), without a significant heterogeneity in the data (I(2) = 0.0%, P = 0.456). CONCLUSIONS: Increased cyclin D1 expression level detected by immunohistochemistry is associated with good progression-free survival for bladder cancer. Because of the limited number of studies, further well-designed prospective studies are warranted to confirm the findings from our study.