MUC1 and neoplasm: Since TGF-β acts as a tumor promoter in high-MUC1 PDA cell lines and as a tumor suppressor in low-MUC1 PDA cell lines, it makes sense that neutralizing TGF-β in high-MUC1 cells (HPAFII), reduced tumor growth as the tumor promoting effect of TGF-β was inhibited by the antibody.