JUN and hepatocellular carcinoma: In HCC, TGF-β transcriptionally activates LINC02551, encoding the 174-aa peptide JunBP, and the resulting JunBP binds to c-Jun and promotes its phosphorylation activation, thereby promoting HCC metastasis (Fig. 3A), and the activated c-Jun will also recruit more transcription factor SMAD3 to the promoter region of the LINC02551, forming a positive feedback to promote metastasis [75].