TGFB1 and hepatocellular carcinoma: By treating HCC cells that express MUC1 with exogenous TGF-β1, TGF-β type I receptor (TβRI) inhibitors, TGF-β1 siRNA or activator protein 1 (AP-1) inhibitors, researchers have found that MUC1-induced autocrine TGF-β promotes cell migration and invasion through the c-Jun N-terminal kinase (JNK)/AP-1 pathway [60].