GAST and colon adenocarcinoma: Alternatively, it is known that gastrin gene expression is greater in colonic adenocarcinomas than in adenomas (Watson et al, 1999b) and in a series of GI cell lines transfected to over-express the gastrin gene, there was down-regulation of gene and protein expression of classical CCK-2, but not Intron IV CCK-2, receptor isoforms (S Evans, personal communication).