Recently, there has been an increasing interest in the diagnostic and prognostic usefulness of tumor-associated antigen of embryonic and fetal origin. Many approaches have been attempted to make an early diagnosis of the pancreatic cancer, where a specific screening blood test for the pancreatic cancer is required. By using antiserum to fetal pancreas, Banwo et al, discovered an oncofetal antigen that was present in human fetal pancreas, pancreatic tumor tissue, and sera from patients with the pancreatic cancer. Pancreatic oncofetal antigen (POA) was considered to be an oncofetal antigen for human pancreas, and its measurement seemed to be useful in the diagnosis of pancreatic cancer. But elevated levels of POA were also observed in the serum of some patients with cancer of the stomach, lung, colon, or liver as well as in the serum of some pregnant women and others with certain benign conditions. In summary, combined assay with various tumor markers was considered to be useful for the diagnosis of pancreatic cancer.