In this multicentre retrospective analysis, the morphological type of IPMN appears to be an independent predictor of patient prognosis.

Background. Pancreatic cancer has a poor prognosis, and early diagnosis of carcinoma and discrimination between malignant and benign conditions are difficult. Many pancreatic cancer‐associated antigens, such as CA 19‐9, DU‐PAN‐2, YPan‐1, and SPan‐1, have been studied. However, expression of Tn, sialosyl‐Tn, and T antigens in tissues of different types of pancreatic neoplasms has not been investigated systematically. Moreover, little is known about the distribution of different types of apomucins in the pancreas. Methods. The expression of Tn, sialosyl‐Tn, and T antigens and DF3 (mammary type apomucin) and intestinal MRP (intestinal type apomucin) was examined immunohistochemically in 47 pancreatic tumors: 36 invasive ductal carcinomas, 5 intraductal papillary tumors, and 6 adenomas. Results. In normal pancreatic tissues, neither Tn nor sialosyl‐Tn antigen was expressed. In contrast, expression of both Tn and sialosyl‐Tn antigens was observed in all the invasive ductal carcinomas and intraductal papillary tumors. None of the adenomas expressed both Tn and sialosyl‐Tn. DF3 antigen was expressed in all invasive ductal carcinomas but not in intraductal papillary tumors, whereas intestinal MRP was expressed in all the intraductal papillary tumors but not in the invasive ductal carcinomas. Conclusions. The results from this study suggest that the expression of the mucin core protein and mucin carbohydrate antigens is correlated with the biologic behavior of pancreatic tumors. In particular, the expression of mammary type mucin core protein and intestinal type mucin core protein showed a striking contrast between invasive ductal carcinomas with a poor prognosis and intraductal papillary tumors with a favorable prognosis.

Background: Many patients with invasive ductal carcinoma of the pancreas (IDC) have a poor outcome. MUC4 expression has been implicated as a marker for diagnosis and progression of IDC, but there are no studies of the relation between MUC4 expression and patient prognosis in IDC. Aims: To investigate the prognostic significance of MUC4 expression in IDC. Methods: The expression profiles of MUC4, ErbB2, p27, and MUC1 were investigated in IDC tissues from 135 patients by means of immunohistochemistry. Results: MUC4 was expressed in 43 of the 135 patients with IDC (31.9%). The survival of 21 patients with high MUC4 expression (.20% of neoplastic cells stained) was significantly worse than that of the 114 patients with low MUC4 expression (,20% of neoplastic cells stained) (p = 0.0043). Univariate analysis showed that high MUC4 expression (p = 0.0061), large primary tumour status (.T2) (p = 0.0436), distant metastasis (p = 0.0383), lymphatic invasion (p = 0.0243), and surgical margins (p = 0.0333) were significant risk factors affecting the outcome of patients with IDC. Backward stepwise multivariate analysis showed that MUC4 expression (p = 0.0121), lymph node metastasis (p = 0.0245), and lymphatic invasion (p = 0.0239) were significant independent risk factors. ErbB2, p27, and MUC1 were not independent risk factors. Conclusions: This study shows that MUC4 expression in IDC is a new independent factor for poor prognosis and predicts the outcome of patients with IDC.

Previously it has been found that the MUC2 gene for intestinal type secretory mucin is highly expressed in intraductal papillary mucinous tumors (IPMT), which are characterized by non-invasive growth and a favorable outcome. In contrast, MUC2 mRNA is rarely expressed in invasive ductal carcinomas (IDC), which have poor outcomes. The gastric type secretory mucin, MUC5AC, is strongly expressed in the surface mucous cells of gastric mucosa. As both MUC2 and MUC5AC mucins share the characteristics of forming highly viscous gels, it is expected that not only MUC2 mucin expression but also MUC5AC mucin expression may be associated with a favorable prognosis in patients with pancreatic tumors. MUC5AC mucin gene expression was examined in 24 cases of IPMT and 38 cases of IDC by in situ hybridization using a digoxigenin-labeled oligonucleotide. The results were compared with MUC2 mucin gene expression. Neither MUC5AC mRNA nor MUC2 mRNA was detected in normal pancreatic tissues. MUC5AC mRNA was expressed in 20 of 24 cases of IPMT (83%) and in five of 38 cases of IDC (13%). In contrast, MUC2 mRNA was expressed in 14 of 24 cases of IPMT (58%) and in none of the 38 cases of IDC (0%). The expression rates of MUC5AC mRNA and MUC2 mRNA in IPMT were significantly higher than those in IDC (P< 0.001, respectively). Intraductal papillary mucinous tumors are characterized by three histological types: (i) villous dark cell type; (ii) papillary clear cell type; and (iii) compact cell type. The villous dark cell type generally expressed both MUC5AC+ and MUC2+ genes. Alternatively, the papillary clear cell type and the compact cell type usually showed MUC5AC+ and MUC2- expression. Patients with MUC5AC mRNA expression had a significantly better survival prognosis than those with no MUC5AC mRNA expression (P< 0.005). In conclusion, MUC5AC gene expression occurs in a majority of IPMT cases, even in those with no MUC2 production. MUC5AC expression can be

The expression of MUC-1 mucin (membrane-associated mucin) and MUC-2 mucin (secretory mucin) were immunohistochemically examined in 46 invasive ductal carcinomas (IDC) and 16 intraductal papillary mucinous tumors (IPMT) of the pancreas. Intraductal papillary mucinous tumors usually reveal expansive growth. However, of the 16 IPMT examined in the present study, three showed an invasive growth pattern, which was similar to 'mucinous carcinoma', around the non-invasive growth areas. Of 46 IDC, MUC-1 mucin detected by monoclonal antibodies, DF3 and MY.1E12, was expressed in 44 cases (96%) and in 45 cases (98%), respectively, whereas MUC-2 mucin detected by polyclonal antibody, anti-MRP, was not expressed in any of the cases (0%). In contrast, in the non-invasive growth areas of the 16 IPMT, MUC-1 mucin detected by DF3 and MY.1E12 was expressed in four cases (25%) and in six cases (38%), respectively, whereas MUC-2 mucin detected by anti-MRP was expressed in 13 cases (81%). The invasive growth areas of the three IPMT showed positive expression of MUC-1 mucins detected by DF3 and MY.1E12, although the non-invasive growth areas showed negative expression of MUC-1 mucins, except for their focal positive expression in one of the three cases. These findings indicate that the invasive growth areas of IPMT acquire a characteristic of MUC-1 mucin expression that is usually seen in IDC.