Molecular profile of apomucin and p53 protein as predictors of malignancy in intraductal papillary mucinous neoplasms of the pancreas.

Background/aims: Invasive intraductal papillary mucinous neoplasms (IPMNs) of the pancreas show poor prognosis similar to ductal adenocarcinomas. The aim of this study was to evaluate the molecular indicators of invasion and risk factors of recurrence of IPMNs.

Methodology: For 46 curative resections of IPMNs, we analyzed the expression of apomucin antigens (MUC1, MUC2 and MUC5AC), p53 and Ki67 using resected specimens.

Results: All 46 IPMNs were classified into 4 groups; MUC1+/p53+, MUC1+/p53-, MUC2+ and MUC1-/MUC2-. The incidence of MUC1 expression increased according to the grade of dysplasia and all of 5 invasive carcinomas expressed MUC1. None of the invasive carcinoma, but almost half of IPMNs of non-invasive carcinoma and sever dysplasia expressed MUC2. Additionally, p53 expression was limited to invasive IPMNs and a non-invasive IPMN which recurred after the operation. The Ki67 labeling index was increased according to the grade of dysplasia and was highest in the MUC1+/p53+ group. In the MUC2+ cases, Ki67 labeling index was significantly higher than that in the MUC1-/MUC2- cases. MUC5AC was expressed in all IPMNs.

Conclusions: The expression of MUC1, MUC2 and p53 might be indicators of malignancy and the expressions of MUC1 and p53 were the predictors of tumor invasion and recurrence.