MicroRNA-30 mediates cell invasion and metastasis in breast cancer.

Despite the great progress in recent years, many aspects of the pathogenesis and progression of breast cancer remain unclear. A better understanding on the molecular mechanisms underlying metastasis and recurrence is crucial to improve the treatment of this lethal disease. MCF-7 cells were xenografted into mice until visible tumors developed, and the cells from tumor tissue and adjacent normal tissue were cultured with 3 passages as mass tumor (MT) cells and invasive tumor (IT) cells, respectively.