Overexpressions of MicroRNA-9 and MicroRNA-200c in Human Breast Cancers Are Associated with Lymph Node Metastasis

PURPOSE: The aim of this study was to investigate the relationship between the expressions of microRNA-9 (miR-9) and microRNA-200c (miR-200c) in human breast cancers and clinicopathological features. METHODS: We investigated the expressions of miR-9 and miR-200c in 68 patients with breast cancers using the quantitative reverse transcription-polymerase chain reaction method, and assessed the E-cadherin status using the immunohistochemistry method. RESULTS: The relative expression levels of miR-9 and miR-200c in breast cancer patients with lymph node metastasis were higher than that of patients without lymph node metastasis. The expression of miR-9 correlated inversely with E-cadherin expression. CONCLUSIONS: The results showed that higher expressions of miR-9 and miR-200c in human breast cancers were associated with lymph node metastasis. This study indicated that the elevation of miR-9 and miR-200c in human breast cancers can induce an invasive phenotype and may serve as a molecular diagnostic marker for patients with breast cancer.