Gg. Finley et al., EXPRESSION OF THE GASTRIN GENE IN THE NORMAL HUMAN COLON AND COLORECTAL ADENOCARCINOMA, Cancer research, 53(12), 1993, pp. 2919-2926
Gastrin, produced in the G-cells of the gastric antrum and regulating
acid secretion in the stomach, also acts as a trophic factor in the ga
strointestinal tract. Because of its possible role in colon cell proli
feration and differentiation, evidence for its presence in normal colo
rectal mucosa and adenocarcinoma was sought. Utilizing tumors and matc
hed normal mucosa from 26 patients, mature gastrin and progastrin were
studied by immunohistochemistry. In normal colonic mucosal crypts, oc
casional cells stained concordantly for gastrin, progastrin, and chrom
ogranin A, suggesting that they are of neuroendocrine origin. Adenomat
ous polyps stained neither for gastrin nor chromogranin A. In 22 of 23
adenocarcinomas, more than 50% of tumor cells stained for gastrin and
progastrin. The expected gastrin transcript was demonstrable by polym
erase chain reaction and RNase protection in tumors and by polymerase
chain reaction in normal mucosa. Its identity was confirmed by sequenc
ing the polymerase chain reaction product. A larger transcript contain
ing Intron II was present in both cancers and normal mucosa but was ba
rely discernible in the gastric antrum. Aberrant expression of gastrin
may contribute to deregulated proliferation of many colorectal carcin
omas.