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Published on: January 3, 2013
Expression of the Novel Costimulatory Molecule B7-H5 in Pancreatic Cancer
Joshua T Byers1, Alessandro Paniccia1, Jeffrey Kaplan2
1Department of Surgery, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
Background:
This study investigated how the B7-H5 protein, a new member of the B7 family, is expressed in normal human pancreas tissues and examined its expression changes in pancreatic cancer.
Methods:
In this analysis, B7-H5 expression was examined by immunohistochemical staining of frozen specimens from patients undergoing pancreatic resection.
Results:
Membranous B7-H5 protein was expressed on normal ductal epithelium within the pancreas. Other cell types from the normal pancreas, such as acinar cells and islet cells, did not express B7-H5. In adenocarcinoma, B7-H5 staining was decreased or absent. Interestingly, B7-H5 expression in intraductal papillary mucinous neoplasms varied with grade. No B7-H5 expression was found with other cancer types such as neuroendocrine tumors, but normal ducts adjacent to tumors were highly positive.
Conclusions:
The findings showed that B7-H5 expression was restricted to ductal cells in the normal pancreas and the expression was downregulated in pancreatic adenocarcinomas. In addition, the findings showed that B7-H5 expression changes within different stages of dysplasia. The study suggests that loss of the B7-H5 signal may contribute to immune evasion of pancreatic adenocarcinoma. However future studies are needed.
