TGFB1 and cancer: Our study also provided significant contribution to the knowledge of miR-34/449 biological functions furnishing the first evidence that in MDA-MB-231 and DA-MB-468 cells miR-34c and miR-449a act as tumor suppressors and inhibitors of the metastatic potential of cancer cells by targeting TGF-β/SMAD and β-catenin signaling pathways.