[1649] Expression of Glypican-3 (GPC-3), Heat Shock Protein 70 (HSP70), and Glutamine Synthetase (GS) in Non-Exocrine Tumors of the Pancreas: A Tissue Microarray Analysis

R Sela, F Remotti, H Remotti. Columbia University Medical Center, New York, NY

Background: A 3-marker panel of Glypican-3 (GPC-3), Heat Shock Protein 70 (HSP70), and Glutamine Synthetase (GS) has been shown to be sensitive and highly specific for diagnosing well differentiated hepatocellular carcinoma (HCC) on biopsy, when at least 2 of 3 markers are positive. Prior studies on the 3-marker panel have focused on differentiating non-neoplastic liver, dysplastic liver nodules, hepatic adenomas, or focal nodular hyperplasia from HCC. To date no study evaluated expression of these markers in tumors that may present as a solitary metastasis to the liver. Certain non-exocrine pancreatic tumors, including pancreatic endocrine neoplasms (PEN), solid pseudopapillary tumors (SPPT), acinar cell carcinomas (ACC) and pancreatoblastomas (PB) may present as a single liver lesion, in the absence of an identified lesion in the pancreas. In the present study we looked at expression of the 3-marker panel in these pancreatic tumors.
Design: Paraffin-embedded TMAs sampling 59 PEN, 10 SPPT, 2 ACC, and 1 PB were stained for GPC-3 (Santa Cruz Biotechnology, SC-24)), HSP70 (Cell Marque, 261M-96), and GS (Millipore/Chemicon, MAB302). The degree of staining was graded on a scale from 1+ to 3+ and the percentage of positive staining cells was recorded.
Results: Two of three markers were positive in 11 of 59 PEN (19%); all 11 of which co-expressed HSP70 and GS. None of the PEN were positive for all three markers. Seven of 10 (70%) of SPPT were positive for either two (5/10) or three (2/10) markers. Of the five cases positive for two markers, four were positive for HSP70 and GS and one was positive for GPC-3 and GS. Neither the ACC (2 cases) nor the PB (1 case) showed positivity for two or more of the stains.
Conclusions: The immunoprofile of PEN and SPPT of the pancreas, with respect to the 3-marker panel (GPC-3, HSP70, and GS), may overlap with the immunoprofile of hepatocellular carcinomas and may be a diagnostic pitfall if a limited panel of immunohistochemical stains is performed.
Category: Liver & Pancreas

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 205, Tuesday Afternoon


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