[1417] BCL10 Is a New Sensitive and Specific Marker of Pancreatic Acinar Cell Carcinoma

S La Rosa, F Franzi, S Marchet, G Finzi, AM Chiaravalli, D Vigetti, F Sessa, C Capella. Ospedale di Circolo, Varese, Italy; University of Insubria, Varese, Italy

Background: Acinar cell carcinoma (ACC) is a rare pancreatic cancer which may be difficult to distinguish from other pancreatic tumors, especially from islet cell tumors. The diagnosis depends on the demonstration of an acinar differentiation, easily obtained with antibodies recognizing various pancreatic enzymes that, although specific, show different levels of sensitivity. The rarity of this cancer, which also implies an occasional use of these antibodies in most laboratories, may lead to misdiagnosis. The C-terminal portion of the BCL10 protein shows homology with carboxyl ester hydrolase (CEH), an enzyme produced by pancreatic acinar cells. Routinely, anti-BCL10 antibodies are used for the diagnosis of MALT lymphomas.
Design: The aim of this study was to investigate the usefulness of a C-terminal-BCL10 monoclonal antibody (clone 331.1) in the diagnosis of pancreatic ACCs. Using immunohistochemistry, electron microscopy and western blotting, we examined normal pancreases and a series of 107 pancreatic tumors including ACCs, mixed acinar-endocrine carcinomas, ductal adenocarcinomas, intraductal papillary-mucinous, mucinous cystic, serous microcystic, endocrine, and solid pseudopapillary tumors. In addition, various normal tissues, cases of pancreatic metaplasia of the gastro-esophageal mucosa, cases of ectopic pancreas, gastrointestinal endocrine tumors, salivary and breast acinic cancers, gastric adenocarcinomas, four of which showing acinar differentiation, and hepatocellular carcinomas were included in the study.
Results: BCL10-immunoreactivity was restricted to acinar cells of normal and ectopic pancreas, of pancreatic metaplasia and of ACCs. It was ultrastructurally localized in zymogen granules. The BCL10 expression paralleled that of CEH as demonstrated by Western blotting and CEH immunohistochemistry. In addition, the anti-BCL10 antibody proved to be more sensitive in detecting ACCs and pancreatic metaplasia than antibodies directed against other pancreatic enzymes like trypsin, amylase, lipase, and CEH.
Conclusions: We suggest using BCL10 antibody for diagnosing pancreatic ACCs and whenever an acinar differentiation is suspected in gastrointestinal neoplastic and metaplastic lesions. In addition, the opportunity to use BCL10 as a marker of both ACCs and MALT lymphomas has the advantage that a single antibody can be employed for diagnosing two different neoplasms.
Category: Liver & Pancreas

Wednesday, March 11, 2009 9:30 AM

Poster Session V # 237, Wednesday Morning