There are three types of gastric carcinoid characterized by different levels of gastrin: (a) type I associated with a very high gastrinemia resulting from AIG; (b) type II which is present in patients with multiple endocrine neoplasia (MEN) and show elevated levels of gastrin; (c) type III presenting as Zollinger–Ellison syndrome which is the most aggressive variant and showing a normal gastrin level [88]. Here, GAST is linked to multiple endocrine neoplasia.