MUC2 and signet ring cell carcinoma: Several studies demonstrated that MUC2 is expressed in intestinal metaplasia and tumors at earlier stages.25, 26 We analyzed the expression of KLF4 and MUC2 in human gastric cancer samples and found a negative correlation between KLF4 and MUC2 levels in signet ring cell carcinoma and mucinous adenocarcinoma.