MSLN and pancreatic ductal adenocarcinoma: Immunohistochemical staining using two mesothelin (5B2, and MN-1) and three MPF (MPF25, MPF44, and MPF49) antibodies were performed in 218 selected tumor tissues including ovarian serous carcinoma, pancreatic ductal carcinoma, thymic tumors, and malignant mesothelioma.