Expression Of MUC1 And MUC2 In IPMN And Its Clinical Signifinance

Intraductal papillary mucinous neoplasm(IPMN) is an uncommon pancreatic neoplasm with characteristic histology and distinctive clinicobiologic behavior. It is characterized by proliferation of ductal epithelium associated with ductal dilatation, variable mucin production and indolent nature of these tumors. We studied the expression of MUC1 and MUC2 in the IPMNs by immunohistochemistry.Materials and Methods: Eighteen patients with IPMNs who were treated at Department of General Surgery of Changhai Hospital between June 2000 and November 2002 were enrolled in this study (Table 1) . In all cases, pathologic diagnosis was made by examination of surgically removed specimens. Surgical specimens of 18 IPMNs were obtained from the Division of Clinical Pathology, Changhai Hospital. The specimens were fixed with 10% formalin solution and cut at intervals of 4 μm. All the lesions were embedded in paraffin, and histologic sections were cut into 4- μm -thick slices for hematoxylin and eosin (H & E) staining. Pathologic diagnoses of the 18 tumors made by pathologists at the 2 institutes according to the World Health Organization classification were adenomas (n = 6 ) , borderline tumors (n =3 ) , carcinoma (n = 9 ) .Results: In the 18 IPMNs,4 cases were MUCl+,and 17 caseswere MUC2+.The rates of MUC1+ in three subgroups were 0% (0/6) in IPMA,33% ( 1/3 ) in IPMB,33% ( 3/9 ) in IPMC. In 18 IPMNs,expressions of MUC2 were observed in 17 cases .The rates of MUC2++in three subgroups were 50% (3/6) in IPMA,67.7% (2/3) in IPMB,88.9% (8/9) in IPMC. We studied expression of MUC1 and MUC2 in each subgroup of IPMN.Conclusions: Expression of MUC1 and MUC2 was different in IPMN and DAC. DAC was characterized by MUC1+, and IPMN was characterized by MUC2+.This difference maybe help to explain the distinct morphologic features and biologic behavior between DAC and IPMN. Over-expression of MUC2 in IPMN can be taken as further evidence of intestinal differentiation. MUC1 expression is the most reliable marker of invasive carcinoma in IPMN.