Coincidence of fundic glandular hyperplasia and carcinoma of the stomach

The enterochromaffin-like (ECL) cell. Physiological and pathophysiological role

Histamine has a central role in the regulation of gastric acid secretion. This histamine is produced by and released from the enterochromaffin-like (ECL) cell which accordingly has a key-regulatory role in the oxyntic mucosa. Gastrin and the vagal nerves stimulate the formation and release of histamine from the ECL cell. Moreover, gastrin and the vagal nerves also stimulate the proliferation of the ECL cell. An increased ECL cell density may partly explain the increased acid secretion in patients with duodenal ulcer, particularly in patients with Zollinger-Ellison syndrome. The reduced potency of histamine-2 blockers in patients with Zollinger-Ellison syndrome is probably due to increased histamine release by an elevated ECL cell mass. Prolonged and profound hypergastrinemia may lead to ECLomas. Moreover, a proportion of diffuse gastric carcinomas may originate from ECL cells.

Enterochromaffin-like tumour cells in the diffuse but not the intestinal type of gastric carcinomas

Gastrin may play a role in gastric carcinogenesis, as indicated by an increased frequency of gastric carcinomas in patients with pernicious anaemia and the fact some human gastric cancer cell lines carry the gastrin receptor. Recently, it has been shown that the acid-stimulatory effect of gastrin may be solely mediated by histamine release from the enterochromaffin-like (ECL) cell, on which gastrin has a specific trophic effect. We therefore found it of interest to examine human gastric carcinomas for the presence of ECL tumour cells by using silver staining and chromogranin immunohistochemistry. We found evidence of ECL cell-derived tumour cells in 40% of the diffuse gastric carcinomas but no such tumour cells in the intestinal type of gastric carcinoma. This may suggest that diffuse gastric carcinomas, like malignant gastric tumours of the mastomys, are in fact malignant ECLomas.

Therapeutic achlorhydria and risk of gastric cancer

New, powerful gastric secretory inhibitors, such as omeprazole, produce gastric cancer in rats. The mechanism by which the drugs elicit gastric carcinogenesis is considered to depend on the production of therapeutic achlorhydria, with subsequent release in to the circulation of peptides (such as gastrin) which are trophic to the gastric mucosa. It has been argued that the drugs do not pose a carcinogenic risk to man because the neoplastic response to gastric inhibitors in rats is a reaction to a 'toxic' insult; or because rats and humans react differently to the drugs; or because the mechanisms of gastric carcinogenesis are different in the two species. In any case, since most of the powerful gastric secretory inhibitors produce carcinoid tumours in rats, and carcinoid tumours of the human stomach are rare and largely benign, there would be no risk even if the drugs did produce proliferative abnormalities of the human stomach. Not one of the above hypotheses has been confirmed or, indeed, even satisfactorily tested. The mechanisms of the drug-induced gastric carcinogenesis in rats has not been defined and consequently it is not even possible to attempt to guess the risk to man. Until information is available about the effects of the powerful gastric secretory inhibitors on the proliferative indices and patterns of the human gastric mucosa, the drugs must be categorized as too dangerous to use therapeutically, especially since the proposed therapeutic benefits are minimal.