MUC1 and familial pancreatic carcinoma: There are also monoclonal antibodies specific for the extracellular region of the MUC1 subunit MUC1-C (anti-hMUC1 antibody and antibody GP1.4), the former recognizes the MUC1-C protein in pancreatic cancer cells, thereby inhibiting epidermal growth factor (EGF)-mediated extracellular signal-regulated kinase (ERK) phosphorylation and cell cycle protein D1 expression and suppressing MUC1 in vitro and in vivo functions of MUC1.