Concentration and Localization of Carbohydrate Antigen 19–9 in Tissues of Pancreatic Cancer

Carbohydrate antigen (CA) 19-9 concentration in the tissue-extracts of cancerous and noncancerous pancreatic tissues were determined by radioimmunoassay. Pancreatic cancer tissues revealed significantly elevated CA 19-9 concentrations, when compared with chronic pancreatitis, normal adult pancreas, or fetal pancreas tissues. Metastatic liver tumors from pancreatic cancer also showed extremely high CA 19-9 concentrations, and there was no significant correlation between tissue CA 19-9 concentration and serum CA 19-9 level in patients with pancreatic cancer. In addition, positive localization of CA 19-9 was clearly observed in cancer cells of pancreatic cancerous tissues by immunohistochemical study, confirming the remarkable increase of CA 19-9 concentration in tissues of pancreatic cancer, although CA 19-9 was also partially found in non-malignant pancreatic tissues. The results indicated that CA 19-9 would be produced in great quantities by cancer cells in tissues of pancreatic cancer, and thus could be a valuable tumor associated antigen suggesting its clinical use as a tumor marker for cancer of the pancreas.