Background: Pancreatic intraductal papillary mucinous neoplasms (IPMN), morphologically resembling colonic adenomas, often have an indefinable malignant potential. We used a monoclonal antibody (MAb) raised against colonic adenomas, Adnab-9, to identify patients with a better prognosis.
Methods: We assessed Adnab-9-labeled sections of these neoplasms from 50 patients, 13 pancreatic adenocarcinomas, and 32 colonic adenomas using standard immunohistochemical techniques.
Results: 26% of the IPMNs labeled with Adnab-9 as compared to 0% of pancreatic ductal cancers or surrounding benign tissues, (p < 0.001) and 53% of adenomas (p < 0.025). Labeling in IPMNs was usually seen in the noninvasive epithelium suggesting that Adnab-9 is a premalignant marker in these lesions. Labeling of invasive IPMN's identified a group of patients with a superior overall survival (p = 0.027).
Conclusion: Adnab-9 labeling-characteristics appear similar for both IPMNs and adenomatous polyps, suggesting that they are analogous lesions. Adnab-9 labeling may also be a useful prognostic marker for invasive intraductal papillary mucinous neoplasms.