Expression of MUC1 and MUC2 mucins in gastric carcinomas: its relationship with the prognosis of the patients.

Our previous immunohistochemical studies for the expression of MUC1 mucin antigen (which was detected by monoclonal antibody DF3) and MUC2 mucin antigen (which was detected by polyclonal antibody anti-MRP) in pancreatic and intrahepatic bile duct tumors demonstrated that invasive carcinoma with poor outcome showed a pattern of MUC1+ and MUC2- expression, whereas many of the noninvasive tumors with favorable outcome showed a pattern of MUC1- and MUC2+ expression. To clarify the relationship between the expression of these mucin antigens and the biological properties of gastric cancers, the expression of MUC1 and MUC2 mucin antigens was examined immunohistochemically in 136 patients with gastric cancer invading the submucosa or the deeper layer, and the survival of the antigen-positive and antigen-negative patient groups was compared using the Kaplan-Meier method. For MUC1 mucin expression, different glycoforms of MUC1 were examined using four monoclonal antibodies (NCL-MUC-1-CORE, DF3, MY.1E12, and HMFG-1). The patients with MUC1+ mucin antigen staining in the carcinoma showed significantly worse survival than those with MUC1- mucin antigen staining. In contrast, the patients with MUC2+ mucin antigen staining in the carcinoma showed significantly better survival than those with MUC2- mucin antigen staining. In conclusion, MUC1 antigen expression was associated with a poor outcome in patients with gastric cancer, irrespective of its glycosylation status, and MUC1 is thus considered to be a useful prognostic factor for poor outcome in patients. In contrast, MUC2 antigen expression is a prognostic factor associated with a favorable outcome in patients. In addition, combined evaluation of the MUC1 and MUC2 mucin staining is clinically useful to predict outcome in patients with gastric cancer.