SMAD4 and breast carcinoma: In hepatocarcinogenesis, the TGF‐β effector SMAD4 appears to control the transcription of miR‐181b (Wang et al., 2010), whereas TGF‐β induces miR‐181a/b at the post‐transcriptional level through SMAD2/3‐dependent miRNA maturation in breast cancer (Wang et al., 2011).