Differential expression of the CCK-A and CCK-B/gastrin receptor genes in human cancers of the esophagus, stomach and colon.

The expression of cholecystokinin (CCK) and gastrin (G) receptors in human gastrointestinal cancers remains poorly documented and is still of a controversial nature. We have measured the levels of mRNA for CCK-A and CCK-B/gastrin receptors using quantitative reverse transcription-polymerase chain reaction (RT-PCR) in primary digestive cancers and hepatic metastases. CCK-A-receptor mRNA was detected in 5 out of 8 esophageal cancers (0.1-1 fg/microg), in 5 out of 8 gastric cancers (0.05-4.2 fg/microg) and in 5 out of 12 colon cancers (0.1-1 fg/microg RNA). CCK-B/gastrin mRNA was not detected in esophageal cancers but was detected in 7 out of 8 gastric cancers (0.05-5.2 fg/microg), and in only 2 out of 12 colon adenocarcinomas (0.05-1 fg/microg RNA). The expression of the CCK-A receptor in esophageal, gastric and colon cancers and of the CCK-B/gastrin receptor in the majority of gastric adenocarcinomas screened may be an important indicator of the influence of CCK and gastrin of local or systemic origin on the growth of these cancers.