Mesothelin is Commonly Expressed in Pancreatic Adenocarcinoma but Unrelated to Cancer Aggressiveness.

Data on Mesothelin expression in human normal and cancerous tissues is controversial. We employed immunohistochemistry on a tissue microarray from 599 pancreatic cancers and 12 large tissue sections of pancreatitis. Mesothelin expression was highest in pancreatic adenocarcinomas (89%) and adenocarcinomas of the ampulla Vateri (79%), infrequent in pancreatitis and absent in 6 acinus cell carcinomas and normal pancreas. Mesothelin expression was unrelated to pathological tumor stage, grade, metastasis, and tumor infiltrating CD8+ lymphocytes. In conclusion, pancreatic cancer may be ideally suited for putative anti-mesothelin therapies, and mesothelin may represent a suitable biomarker for pancreatic cancer diagnosis, especially on small biopsies.