SMAD3 and cancer: PMEPA1 is induced by the TGF‐β signalling, but meanwhile, it inhibits the phosphorylation of Smad2 and Smad3 to antagonize TGF‐β signalling.23 Considering the negative loop of PMEPA1 and TGF‐β signalling, the phenotype of PMEPA1 in specific cancer needs deeper investigation.