Prognostic and Biological Significance of MicroRNA-127 Expression in Human Breast Cancer

The purpose of this study was to determine the expression of miR-127 and analyze its prognostic and biological significance in breast cancer (BC). A quantitative reverse transcription PCR assay was performed to detect the expression of miR-127 in 15 pairs of BC and corresponding noncancerous tissues. The expression of miR-127 was detected in another 110 BC tissues and its correlations with clinicopathological factors of patients were examined. Univariate and multivariate analyses were performed to analyze the prognostic significance of miR-127 expression. The effects of miR-127 expression on malignant phenotypes of BC cells and its possible molecular mechanisms were further determined. miR-127 was significantly downregulated in BC tissues, and low miR-127 expression was significantly correlated with lymph node metastasis and advanced clinical stage. Patients with low miR-127 showed poorer overall survival than those with high miR-127. Multivariate analyses indicated that status of miR-127 was an independent prognostic factor for patients. Functional analyses showed that upregulation of miR-127 significantly inhibited growth, enhanced apoptosis, and reduced migration and invasion in BC cells by targeting the protooncogene BCL-6. Therefore, miR-127 may be a potential biomarker for predicting the survival of BC patients and might be a molecular target for treatment of human BCs.