Section Review: Oncologic, Endocrine & Metabolic: Gastrin antagonists and gastrointestinal tumours

The role of gastrin in the growth of gastrointestinal tumours is complex, involving both endocrine and autocrine/paracrine pathways. Receptor subtypes, distinct from the classical gastrin/CCK-B receptors which mediate the normal physiological functions of gastrin, are now being identified. These appear to have potential roles in gastrin-associated proliferative pathways in malignant cells. Due to the recent expansion of knowledge in this area, the role of the classical anti-gastrin agents remains unclear. This is especially so for the gastrin/CCK-B receptor antagonists, due to the multiple receptor types now in evidence. However, certain agents may potentially overcome the problem of the different gastrin-mediated mitogenic pathways and the receptor isoforms involved. Although agents which block gastrin secretion, such as somatostatin analogues, might have been expected to be successful at targeting the autocrine/paracrine pathway, clinically, in gastrointestinal adenocarcinomas, they have proven disappoi...