[Studies on a pancreatic oncofetal antigen (POA) in patients with pancreatic cancer].

An enzyme immunoassay for POA prepared by Gelder et al. was developed in our laboratory. Elevated serum POA levels were shown in 70.6% (36/51) of patients with pancreatic cancer. POA levels were related neither to the stage nor to the degree of differentiation of pancreatic cancer. Although POA levels were not elevated in patients with benign diseases of the pancreas, they were elevated in patients with cancer of the hepato-biliary tract. In pancreatic cancer patients with pre-operative high POA levels, serial POA determinations following tumor resection are considered to be useful for detecting recurrence of disease. Employing the unlabeled antibody peroxidase-antiperoxidase (PAP) method, POA was detected in the cytoplasm of cancer cells in 80.0% (28/35) of pancreatic cancer patients, but not in histologically normal pancreatic tissue. Well differentiated cancer cells showed higher POA stainability than less differentiated ones. POA was also detected in fetal pancreas tissues of 22 weeks gestation, but not in those of 12-16 weeks gestation. This result suggests that POA is an oncofetal antigen.