Prognostic role of microRNA-221 in various human malignant neoplasms: a meta-analysis of 20 related studies.
BACKGROUND
MicroRNA-221 (miR-221) has been shown to play an important role in cancer prognosis. In order to evaluate the predictive value of miR-221, we compiled the evidence from 20 eligible studies to perform a meta-analysis.


METHODS
All of relevant studies were identified by searching PubMed, Embase, and Web of Science, and were assessed by further quality evaluation. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) of total and stratified analyses, for overall survival (OS) and recurrence-free survival (RFS), were calculated to investigate the association between high miR-221 expression and cancer prognosis.


RESULTS
We found that high miR-221 expression can predict a poor OS in malignant tumors (pooled HR = 1.55, P = 0.017) but has no significant association with RFS (pooled HR = 1.02, P = 0.942). Further in stratified analyses, high miR-221 expression was significantly associated with a poor OS in Asians (pooled HR = 2.04, P = 0.010) or serum/ plasma subgroup (pooled HR = 2.28, P<0.001), and even showed significantly poor OS (pooled HR = 1.80, P<0.001) and RFS (pooled HR = 2.43, P = 0.010) in hepatocellular carcinoma (HCC) subgroup, but was correlated to a favorable RFS in prostate cancer subgroup (pooled HR = 0.51, P = 0.004).


CONCLUSIONS
Our findings demonstrate that miR-221 is more suitable to predict cancer prognosis in Asians, and it is a promising prognostic biomarker for HCC. The detection of miR-221 in serum or plasma samples may make it become an effective method for monitoring patients' prognosis and assessing therapeutic efficacy in the future.
Department of Urology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China.
Jie
J
Yang
Department of Urology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China.
Jia-yi
JY
Zhang
Department of General Surgery, Nanjing First Hospital Affiliated to Nanjing Medical University, Nanjing, Jiangsu, China.
Jing
J
Chen
Department of Urology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China.
Yang
Y
Xu
Department of Urology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China.
Ning-hong
NH
Song
Department of Urology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China.
Chang-jun
CJ
Yin
D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D009369:Neoplasms / Q000175:diagnosis* / Q000235:genetics*; D011379:Prognosis; D016016:Proportional Hazards Models
D035683:MicroRNAs; C525709:MIR221, human