MUC4 and neoplasm: The serum bound strongly to proteins in cell lysates from MUC4+ PDAC cells such as HPAC and HPAF but not to proteins in cell lysates from MUC4− PDAC cells such as PANC-1 (Fig. S2) or to other MUC4− tumor cells such as T24 bladder carcinoma cells (data not shown).