High expression levels of miR-21 and miR-210 predict unfavorable survival in breast cancer: a systemic review and meta-analysis.
BACKGROUND
MicroRNAs (miRNAs) have been emerging as valuable prognostic biomarkers of breast cancer. We therefore summarized recent research into miRNAs involved in human breast cancer and, further, completed a meta-analysis to predict the role of specific miRNAs in the survival of breast cancer patients.


METHODS
Studies were identified by searching PubMed, Embase and Web of Science. Descriptive characteristics for studies were described, and an additional meta-analysis for specific miRNAs was performed. Pooled hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs) were calculated.


RESULTS
A total of 41 articles including 27 types of miRNAs were found regarding prognostic biomarkers for breast cancer survival, of which, micRNA-21 (miR-21) was the most-studied specific miRNA that appeared repeatedly among the selected classifiers. For the studies evaluating miR-21's association with clinical outcomes, the median HR in the studies was 2.32 (interquartile range [IQR] = 1.04-3.40), and the pooled HR suggested that high expression of miR-21 has a negative impact on overall survival (OS; HR = 1.46, 95% CI, 1.25-1.70; p&lt;0.05) and disease/recurrence-free survival in breast cancer (HR = 1.49, 95% CI, 1.17-1.90; p&lt;0.01). We also found that higher expression levels of miR-210 significantly predicted poorer outcome, with median HR in the reported studies of 4.07 (IQR = 1.54-4.43) and a pooled HR of 2.94 (95% CI, 2.08-4.17; p&lt;0.05).


CONCLUSIONS
These results indicate that miRNAs show promising associations with prognosis in breast cancer. Moreover, specific miRNAs such as miR-21 and miR-210 can predict poor survival rates in breast cancer patients.
Department of Radiotherapy, Changzhou Tumor Hospital, Soochow University, Changzhou - China.
Yiting
Y
Tang
Department of Radiotherapy, Changzhou Tumor Hospital, Soochow University, Changzhou - China.
Xifa
X
Zhou
Department of Radiotherapy, Changzhou Tumor Hospital, Soochow University, Changzhou - China.
Jianfeng
J
Ji
Department of Radiotherapy, Changzhou Tumor Hospital, Soochow University, Changzhou - China.
Ling
L
Chen
School of Radiation Medicine and Protection and Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou - China.|Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions and School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University, Suzhou - China.
Jianping
J
Cao
Department of Radiotherapy, Changzhou Tumor Hospital, Soochow University, Changzhou - China.
Judong
J
Luo
School of Radiation Medicine and Protection and Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Medical College of Soochow University, Suzhou - China.|Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions and School for Radiological and Interdisciplinary Sciences (RAD-X), Soochow University, Suzhou - China.
Shuyu
S
Zhang
D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000401:mortality; D018572:Disease-Free Survival; D005260:Female; D015870:Gene Expression; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D011379:Prognosis; D016016:Proportional Hazards Models
D014408:Biomarkers, Tumor; C524940:MIRN21 microRNA, human; C543800:MIRN210 microRNA, human; D035683:MicroRNAs