Quantitative measurement of serum microRNA-21 expression in relation to breast cancer metastasis in Chinese females.
BACKGROUND
Breast cancer is the most common type of cancer in females. Aberrant expression of microRNA-21 (miR-21) has previously been reported in breast cancer tissue. The aim of this study was to investigate expression levels of serum miR-21 in breast cancer patients and evaluate its prognostic value in Chinese females.


METHODS
Real-time quantitative (RQ)-PCR was used to analyze miR-21 expression in archived serum, tumor tissue, and adjacent normal tissue from 549 participants (326 with breast cancer, 223 without breast cancer). We also analyzed associations between serum miR-21 expression and breast cancer subtypes and patient prognosis. Recurrence and survival were analyzed by using the multivariate Cox proportional hazards model.


RESULTS
Expression of miR-21 was significantly higher in breast cancer tissues compared with normal adjacent breast tissues (P<0.001). The 2(-ΔΔCt) values for serum miR-21 in breast cancer patients versus healthy controls were 9.12±3.43 and 2.96±0.73, respectively. Multivariate Cox proportional hazards model suggested that serum miR-21 expression was an independent poor prognostic factor for both recurrence (hazard ratio [HR]= 2.942; 95% confidence interval [CI]=1.420-8.325; P=0.008) and disease-free survival (HR=2.732; 95% CI=1.038-7.273, P=0.003) in breast cancer.


CONCLUSIONS
Increased serum miR-21 expression level was correlated with poor prognosis of breast cancer patients, indicating that serum miR-21 may be a novel prognostic marker for recurrence and survival of breast cancer patients before resection.
Department of Laboratory Medicine, The First Hospital of Zibo City, Zibo, China.
Guinian
G
Wang
Department of Pharmacy, Zibo Vocational Institute, Zibo, China.
Longzi
L
Wang
Department of Surgical Medicine, The First Hospital of Zibo City, Zibo, China.
Sijing
S
Sun
Department of Laboratory Medicine, The First Hospital of Zibo City, Zibo, China.
Juan
J
Wu
Key Laboratory of Biomedical Engineering, Shandong Wanjie Medical College, Zibo, China.
Qinglu
Q
Wang
D014408:Biomarkers, Tumor / Q000235:genetics; D001940:Breast / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D035683:MicroRNAs / Q000097:blood*; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D016016:Proportional Hazards Models; D060888:Real-Time Polymerase Chain Reaction
D014408:Biomarkers, Tumor; C524940:MIRN21 microRNA, human; D035683:MicroRNAs
Biomarker; Breast cancer; Prognosis; Serum miR-21