Human cholecystokinin-A receptor is not an oncofetal protein

The CCK-A (cholecystokinin-A) receptor is selectively expressed by human pa ncreatic adenocarcinomas, suggesting a possible role In pancreatic tumorige nesis. In animals, pancreatic CCK receptor expression varies during ontogen y and neoplastic transformation. This study examined the temporal expressio n of CCK receptors in human fetal, postnatal, and adult pancreas to determi ne whether the appearance of CCK-A receptors in pancreatic adenocarcinomas reflected oncofetal antigen or pancreatic neoantigen expression. Messenger ribonucleic acid (mRNA) was isolated from six paraffin-embedded normal panc reatic autopsy specimens ranging in age from 17 weeks postfertilization thr ough 26 days following full-term delivery, and samples of adult human tissu es, including pancreas and pancreatic adenocarcinoma. Using reverse transcr iption-polymerase chain reactions, CCK-B receptor mRNA was expressed in all specimens of normal fetal and postnatal human pancreas, adult pancreas, an d pancreatic adenocarcinomas. CCK-A receptor mRNA was selectively expressed only in pancreatic adenocarcinomas. These data suggest that selective CCK- A receptor expression in pancreatic adenocarcinomas reflects neoantigen exp ression in humans.