SMAD5 and cancer: As we know, TGF‐β is a classical inducer of EMT to drive tumour cell migration, invasion, and metastasis in many carcinomas.36 As a TGF‐β‐inducible gene, PMEPA1 regulated multiple biological process in several types of cancer.16, 20, 37 Some reports showed PMEPA1 accelerates the metastasis and EMT through TGF‐β signalling.35 Nevertheless, we demonstrated PMEPA1 promoted migration and invasion, and induced EMT in CRC by activating the BMP signalling pathway with phosphorylation of Smad1 and Smad5.