In our study, ectopicexpression of miR-302/367 cluster in the breast cancercells downregulated expression of all of the investigatedTGF-βmediators, including TGFBR2, BUB1, RHOC,AKT1, MAPK1, MAPK14 and SMAD3. These findingsindicate a strong suppressive effect of miR-302/367 clusteron the TGF-βsignaling (Fig .4). This evidence concerns the gene MAPK1 and neoplasm.