The prognostic value of cyclin D1 expression in the survival of cancer patients: a meta-analysis

Background The relationship between the expression of cyclin D1 and cancer prognosis and outcomes in different malignancies has not been fully elucidated. Aims In the presented meta-analysis, we assessed the association between the expression level of cyclin D1 with overall survival (OS) in several cancers. Methods Eligible studies were identified using PubMed, EMBase, Scopus, Web of Sciences and Cochrane Library databases. For the prognostic meta-analysis, study-specific hazard ratios (HRs) of tissue cyclin D1 for survival were obtained. Finally we pooled data derived from one hundred and eight studies comprising 19,224 patients with 10 different cancer types. Results In the pooled analysis, high expression of cyclin D1 was significantly related to a poor OS with a pooled HR of 1.11 (95% CI: 1.02–1.20, P = 0.015; random-effects). Sub-group analysis revealed that high expression of cyclin D1 was related to worse OS of head and neck cancers (HR = 2.08, 95% CI: 1.75–2.47; P < 0.001), but not in breast (HR = 1.033, 95% CI: 0.873–1.223, P = 0.702), gastrointestinal (HR = 1.025, 95% CI:0.824–1.275; P = 0.825), bladder (HR = 0.937, CI: 0.844–1.041; P = 0.225) and in lung cancer patients (HR = 1.092, CI: 0.819–1.455; P = 0.549). Conclusion Further large, prospective, and well-designed trials are warranted to elucidate the precise clinical importance of cyclin D1 overexpression in the prognosis of cancer patients receiving different treatment regimens.