CCK-A and -B receptors in normal and malignant human pancreas

Cholecystokinin (CCK) may mediate pancreatic carcinogenesis. However, the role of CCK-A (A) and -B (B) receptors in that process remains unclear. Thus, expression of A and B receptors in fresh normal and malignant human pancreas was examined by the reverse transcription-polymerase chain reaction (RT-PCR). RNA isolated from 5 samples of normal pancreas and 13 samples of pancreatic carcinoma was subjected to RT-PCR employing A- and B-specific primers. In all cases, normal pancreas expressed only B receptors. However, A and B receptors were identified on all pancreatic carcinomas examined. In situ hybridization, employing specific riboprobes, localized A receptor expression to ductal cells, the origin of most pancreatic cancers. A gene amplification or rearrangement was not detected in tumors by Southern analysis. Thus, A receptors are specifically expressed by human malignant, compared to normal pancreas. A receptors may serve as diagnostic and therapeutic targets in pancreatic malignancy.