OVEREXPRESSION OR ECTOPIC EXPRESSION OF MUC2 IS THE COMMON PROPERTY OF MUCINOUS CARCINOMAS OF THE COLON, PANCREAS, BREAST, AND OVARY

Mucinous carcinomas of the colorectum have been reported to overexpres s the intestinal mucin MUC2. The purpose of this study was to determin e whether this alteration is shared by mucinous tumours of the ovary, breast, and pancreas. A total of 40 breast carcinomas (22 of mucinous and 18 of ductal invasive type), 39 ovarian adenocarcinomas (16 mucino us, 23 serous), 47 colorectal carcinomas (25 mucinous and 22 non-mucin ous), and 41 pancreatic adenocarcinomas (14 mucinous, 27 non-mucinous) mere investigated by immunohistochemistry with the anti-MUG2 monoclon al antibody 4F1 and the expression pattern was ranked. MUC2 mucin is e xpressed in the normal colonic epithelium; in the normal epithelium of the breast, ovary, and pancreas, it was not detectable by immunohisto chemistry or by reverse transcriptase-polymerase chain reaction (RT-PC R). In agreement with previous reports, the colonic mucinous carcinoma s differed significantly from the non-mucinous carcinomas by strong MU C2 expression. In all mucinous carcinomas of the ovary, breast, and pa ncreas, ne novo expression of the MUC2 gene was observed, which differ entiated mucinous and nonmucinous carcinomas of these tissues (P<0.001 ). The overexpression or ectopic expression of the MUC2 gene exhibited by mucinous carcinomas of four organs indicates a common genetic lesi on associated with the mucinous tumour phenotype. (C) 1997 by John Wil ey & Sons, Ltd.