MUC2 GENE-EXPRESSION IS FOUND IN NONINVASIVE TUMORS BUT NOT IN INVASIVE TUMORS OF THE PANCREAS AND LIVER - ITS CLOSE RELATIONSHIP WITH PROGNOSIS OF THE PATIENTS

We have previously reported that MUC2 apomucin was highly expressed in noninvasive tamers of the pancreas (intraductal papillary tumor [IdPT ]) and liver (bile duct cystadenocarcinoma [BdCC]), which show more fa vorable outcomes than invasive carcinomas. In contrast, MUC2 was rarel y expressed in invasive carcinomas of the pancreas (invasive ductal ca rcinoma [IDC]) and the liver (invasive cholangiocarcinoma [ICC]), In t he present study, we examined localization of MUC2 messenger RNA (MUC2 mRNA) by using a complementary DNA (cDNA) probe for the MUC2 tandem r epeat for in situ hybridization (pHAM1). Localization of MUC2 apomucin was determined by using an antibody directed against MUC2 apomucin (a nti-MRP) for immunohistochemistry study. Eleven IdPTs and 10 IDCs of t he pancreas, and 8 BdCC and 8 ICCs of the Liver were examined. Nine (8 2%) of 11 IdPTs showed positive expression of MUC2 mRNA hi the neoplas tic cells, whereas none (0%) of the IDCs showed expression of MUC2 mRN A. Six (75%) of die 8 BdCCs showed positive expression of MUC2 mRNA in the neoplastic cells, whereas none (0%) of the 8 ICCs showed expressi on of MUC2 mRNA. The localization of MUC2 mRNA and. that of MUC2 apomu cin usually coincided, although a few cases (1 IDC, 1 BdCC, and 1 ICC) showed focal expression of MUC2 apomucin despite the absence of detec table MUC2 mRNA. These results indicate that the expression of MUC2 ap omucin in IdPTs and BdCCs correlates with expression of MUC2 mRNA. In both patient groups with pancreatic tumors and hepatic tumors, patient s with positive MUC2 mRNA expression in the tumors showed significantl y better survival than those with negative MUC2 mRNA expression in the tumors. The production of MUC2, an abundant extracellular mucin, by m ost IdPTs and BdCCs may be correlated with tumors that display lower l evels of invasion and metastasis. Copyright (C) 1997 by W.B. Saunders Company.