Specifically, several studies have demonstrated that key components of the ghrelin system (e.g. native ghrelin, GHSR1a and GHSR1b) are expressed in various tumors including pituitary adenomas and breast and prostate cancer, thus suggesting a possible autocrine or paracrine role of ghrelin system in the pathogenesis of these tumors (for review see: [9]). The gene discussed is GHRL; the disease is pituitary gland adenoma.