title: Reduced expression levels of let-7c in human breast cancer patients.
abstract: Circulating microRNAs (miRNAs) are important in the diagnosis of a number of diseases, since serum or plasma miRNAs are more stable compared with miRNA isolated from blood samples. The aim of the present study was to investigate the association between the expression levels of serum let-7c miRNA and the clinical diagnosis of breast cancer (BC). The circulating let-7c levels of 90 BC patients and 64 healthy controls were determined by performing a reverse transcription-quantitative polymerase chain reaction assay. The results demonstrated that let-7c expression was downregulated in the BC tissues compared with the paracarcinoma control tissues. In addition, the let-7c expression in the serum of BC patients was significantly lower compared with the healthy controls (P<0.01). Using a cutoff value of 0.374×103copies/ml, the serum expression levels of let-7c exhibited 87.5% sensitivity and 78.9% specificity for distinguishing BC patients from healthy controls (area under the receiver operating characteristic curve, 0.848; 95% confidence interval, 0.785-0.911). Furthermore, the results demonstrated that the serum expression levels of let-7c were significantly higher in premenopausal compared with postmenopausal patients (P<0.05), supporting the hypothesis that postmenopausal status may affect the serum expression levels of let-7c. However, no statistically significant differences were detected in the serum levels of let-7c between ER (or PR)-positive and -negative patients. Therefore, the current study hypothesized that serum let-7c may be used as a novel and valuable biomarker for the diagnosis of BC.
authors: Key Laboratory of Tumor Molecular Biology, Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, Shandong 264003, P.R. China.
authors: Xin-Xin
authors: XX
authors: Li
authors: Department of Clinical Medicine, Affiliated Hospital of Binzhou Medical University, Yantai, Shandong 264003, P.R. China.
authors: Shu-Yan
authors: SY
authors: Gao
authors: Key Laboratory of Tumor Molecular Biology, Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, Shandong 264003, P.R. China.
authors: Ping-Yu
authors: PY
authors: Wang
authors: Department of Clinical Medicine, Affiliated Hospital of Binzhou Medical University, Yantai, Shandong 264003, P.R. China.
authors: Xue
authors: X
authors: Zhou
authors: Key Laboratory of Tumor Molecular Biology, Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, Shandong 264003, P.R. China.
authors: You-Jie
authors: YJ
authors: Li
authors: Key Laboratory of Tumor Molecular Biology, Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, Shandong 264003, P.R. China.
authors: Yuan
authors: Y
authors: Yu
authors: Key Laboratory of Tumor Molecular Biology, Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, Shandong 264003, P.R. China.
authors: Yun-Fei
authors: YF
authors: Yan
authors: Key Laboratory of Tumor Molecular Biology, Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, Shandong 264003, P.R. China.
authors: Han-Han
authors: HH
authors: Zhang
authors: Department of Clinical Medicine, Affiliated Hospital of Binzhou Medical University, Yantai, Shandong 264003, P.R. China.
authors: Chang-Jun
authors: CJ
authors: Lv
authors: Department of Pathology, Affiliated Yuhuangding Hospital, Medical College of Qingdao University, Yantai, Shandong 264000, P.R. China.
authors: Hui-Hui
authors: HH
authors: Zhou
authors: Key Laboratory of Tumor Molecular Biology, Department of Biochemistry and Molecular Biology, Binzhou Medical University, Yantai, Shandong 264003, P.R. China.
authors: Shu-Yang
authors: SY
authors: Xie
keywords: breast cancer; circulating miRNA; let-7c; predictive factor; receiver operating characteristic analysis