MiR-335 exerts its inhibitory effects on breast cancer metastasis through direct suppression of the genes encoding the SOX4 transcription factor and the extracellular matrix component tenascin C. In addition, Valastyan et al. [35] reported that miR-31 is downregulated in metastatic breast cancer cells and inhibits the invasiveness and metastasis of these cells via direct targeting of multiple metastasis-associated genes, such as RhoA and ITGA5 (encoding integrin 5α). This evidence concerns the gene SOX4 and breast cancer.