“…Since the development of sensitive gastrin radio-immunoassays in the 1960s, it has become clear that chronic hypergastrinemia is not an infrequent finding and that it has both physiologic and pathophysiological causes [10,37,38,39,40,41]. The physiological causes can be a response to anything that results in prolonged hypo/achlorhydria, which can include processes as varied as the chronic use of potent acid suppressive drugs, gastric infections such as Helicobacter pylori, and postsurgical procedures such as vagotomy or other gastric acid-reducing surgeries [10,37,38,39,40,41]. Pathological causes of chronic hypergastrinemia include any disease causing hypo-/achlorhydria (including potent gastric anti-secretory drugs such as PPIs, pernicious anemia, atrophic gastritis, failure to develop functional parietal cells because of an inherited disorder such as defects in the genes encoding the gastric H + K + acid pump) [10,39,40,41,50]; overproduction of gastrin due to the presence of NETs ectopically secreting gastrin (gastrinoma), as well as other disease states such as chronic gastric infections such as Helicobacter pylori, renal failure, and massive small bowel resections [10,21,37,38,39,40,41].…”