Utility and Limitations of Mesothelin Immunohistochemistry for Pancreatic Neoplasia in Both Surgical and Fine Needle Aspiration Materials
JP Glass, RE Donohue, LA Cerilli. University of New Mexico, Albuquerque, NM
Background: Previous studies have shown that mesothelin overexpression can be detected by immunohistochemistry in pancreatic adenocarcinoma. Our study attempts to confirm these results and further characterize immunohistochemical mesothelin staining in both fine needle aspirates and surgical materials from a spectrum of pancreatic neoplasms.
Design: Immunohistochemical staining for mesothelin was performed on resection or biopsy specimens from: 23 ductal adenocarcinomas, 15 ampullary adenocarcinomas, 4 distal common bile duct adenocarcinomas, 6 mucinous neoplasms, 3 serous cystadenomas, 4 benign cysts, 1 solid pseudopapillary tumor, and 2 chronic pancreatitis cases. Mesothelin staining was also performed on cell block material from 37 fine needle aspirates of pancreatic adenocarcinoma. Positive staining in the surgicals was defined as at least 2+ (moderate intensity) apical staining in at least 5% of cells. Positive staining in the aspirations was defined as any adenocarcinoma cells with at least 2+ apical staining.
Results: 24 of 42 resected or biopsied adenocarcinomas (ductal, ampullary, and distal common bile duct) stained for mesothelin, while none of the non-carcinoma cases (0 of 16) showed positive staining (p = 0.0000784). In addition, only 3 of the 15 ampullary adenocarcinomas were positive for mesothelin, compared with 21 of 27 of the non-ampullary adenocarcinomas (p = 0.0002884). 27 of the 37 pancreatic adenocarcinoma fine needle aspirates were also positive for mesothelin. Of the 10 negative cases, limited material was present for evaluation in 3 cases (30%).
|TOTAL||MESOTHELIN +||MESOTHELIN -|
|PANCREATIC DUCTAL ADENOCARCINOMA||23||18||5|
|BILIARY (BILE DUCT) ADENOCARCINOMA||4||3||1|
|ALL MUCINOUS NEOPLASMS||6||0||6|
|INTRADUCTAL PAPILLARY MUCINOUS NEOPLASM||4||0||4|
|MUCINOUS CYSTIC NEOPLASM||2||0||2|
|SIMPLE CYST OR PSEUDOCYST||4||0||4|
|FINE NEEDLE ASPIRATIONS OF PANCREATIC ADENOCARCINOMA||37||27||10|