Along with the highly expressed miR-146b-5p, the miRNAs miR-221/222, miR-181a/b and miR-155 may actually attenuate TGF-β signal transduction by repressing not only the SMAD intracellular signaling components, but also activin receptor 1B (ACVR1B) and bone morphogenetic factor 8A (BMP8A), and contribute with tumor progression. The gene discussed is TGFB1; the disease is neoplasm.