Decreased expression of microRNA-206 in breast cancer and its association with disease characteristics and patient survival

Objectives MicroRNA-206 (miR-206) is downregulated in many human malignancies, which correlates with tumour progression. This study characterized the contribution of miR-206 to the initiation and progression of human breast cancer.Methods Consecutive primary breast cancer patients who received radical resection were enrolled. Breast cancer tissue samples were obtained during surgery. MiR-206 levels in matched pairs of cancer tissue and normal adjacent tissue (NAT) samples were examined using quantitative reverse transcription–polymerase chain reaction. The relationship between miR-206 levels and clinicopathological characteristics and overall survival was also investigated.Results In 128 patients with breast cancer, miR-206 was downregulated in 119 (93%) tumour tissue compared with their matched NAT samples. Decreased miR-206 was significantly associated with advanced clinical stage and lymph node metastasis. Univariate and multivariate Cox proportional hazard regression analysis revealed that a low miR-206 level was an unfavourable prognostic factor for overall survival, in patients with breast cancer.Conclusions This study indicated that miR-206 may be a good candidate as a novel prognostic indicator in breast cancer patients.