[Oncofetal proteins of the exocrine pancreas]

Specific pancreatic oncofetal proteins have been discovered in man and a species of hamster using polyclonal antisera against fetal pancreatic extracts. Two main components in the Mr range of 80 kDa and 58 kDa (hamster) and 110 kDa and 58 kDa (man) were detected in pancreatic fetal extracts, by the "Western blot" technics. Two monoclonal antibodies, namely J28 directed against the human 110 kDa component (FAP protein) and B4 directed against the hamster 58 kDa component (FP protein) have been prepared. The B4 cross-reacts with the homologous human antigen. These monoclonal antibodies have shown that both proteins are antigenically unrelated, although they share common properties such as association to development of exocrine pancreas and high tissue specificity. The expression of both proteins increases in the case of pancreatic cancer but localisation varies. FAP protein is found in peritumoral acinar tissue, whereas FP protein is expressed in transformed cells. FAP protein is a serum marker for pancreatic pathologies and combined with CA 19-9 antigen assay it provides a serum test which is almost specific for cancer of the pancreas with near 100% sensitivity.