Immunohistochemical analysis of molecular biological factors in intraductal papillary-mucinous tumors and mucinous cystic tumors of the pancreas

Background: To investigate the malignancy and differentiation of intraductal papillary-mucinous tumors (IPMTs) and mucinous cystic tumors (MCTs) of the pancreas, clinicopathologic characteristics and immunohistochemical features were analyzed. Methods: The clinicopathologic characteristics and immunohistochemical features of 24 patients with IPMT and 8 with MCT who underwent pancreatic resections at our hospital were examined. Immunohistochemical features analyzed included expression of p53 protein, proliferating cell nuclear antigen, integrins, interleukin-1 receptor type I, and hormone-associated receptors, and the factors correlated with malignancy were identified by multiple logistic regression. Results: Among the IPMTs, there were 16 intraductal papillary adenomas, 5 intraductal papillary adenocarcinomas, and 3 moderate dysplasias. Among the MCTs, there were 6 mucinous cyst adenomas and 2 mucinous cyst adenocarcinomas. Multivariate analysis revealed that of the clinicopathologic characteristics, only the presence of mural nodules ( odds ratio ( OR) 7.12, P = 0.044) was independently correlated with the malignancy of IPMTs, and that of the immunohistochemical features, only alpha(6) integrin subunit expression was independently correlated with malignancy of pancreatic mucinous tumors ( OR 15.6, P = 0.036), especially IPMTs ( OR 35.7, P = 0.012). Conclusion: These results indicate that alpha(6)-containing integrin expression can be a significant marker of malignancy in pancreatic mucinous tumors.