Clinical significance of MicoRNA-155 expression in human breast cancer

Background The aim of this study is to investigate clinical significance of miR-155 expression in breast cancer. Methods TaqMan real-time RT-PCR was performed to detect miR-155 expression in breast cancer tissues. The correlation of miR-155 expression with clinicopathological factors and prognosis of breast cancer patients was analyzed. Then, the prognostic value of miR-155 expression was analyzed by univariate and multivariate analyses. Moreover, the effect of miR-155 expression on phenotypes of breast cancer cell was determined by antisense technology. Results The relative expression of miR-155 was significantly higher in breast cancer tissues than in corresponding nontumor tissues. High miR-155 expression was correlated with higher tumor grade, advanced tumor stage and lymph node metastasis (P = 0.012, 0.001, and 0.003, respectively). Kaplan–Meier survival analysis indicated that the disease-free and overall survival rates of high miR-155 group were significantly lower than those of low miR-155 group (P = 0.038 and 0.029, respectively). Multivariate analysis showed that high miR-155 expression was a poor prognostic factor (P = 0.009). Furthermore, antisense targeting miR-155 could inhibit growth, induce cell arrest in G0/G1 phase, enhance apoptosis, and increase radiosensitivity in breast cancer cells. Conclusions MiR-155 expression might be an independent prognostic factor and a therapeutic target for human breast cancer. J. Surg. Oncol. 2012; 106:260–266. © 2011 Wiley Periodicals, Inc.