GAST and gastrin-producing neuroendocrine tumor: Compared with those of non-gastric origin, patients with gastric gastrinomas had significantly elder age (56.3 ± 11.2 vs. 39.7 ± 17.4, p = 0.024) and higher gastrin level (512.3 ± 323.3 vs. 207.7 ± 234.7 mg/ml, p = 0.030), however, smaller tumor size (7.3 mm vs. 5.1 mm, P = 0.065).