Acromegaly can be due to eutopic hypothalamic GHRH hypersecretion (gangliocytoma, hamartoma, choristoma, glioma, etc.)or, more often, to ectopic, peripheral GHRH hypersecretion (pancreatic or bronchial carcinoid tumor) that stimulate the normal somatotropes to become hyperplastic and to hypersecrete GH. This evidence concerns the gene GHRH and gangliocytoma.