Thus, we identify type 1 gastric NETs, associated with chronic atrophic gastritis (CAG) of the gastric body and a vitamin B12 deficiency; type 2, associated with Zollinger‐Ellison syndrome in the context of Multiple Endocrine Neoplasia type 1 (MEN1); and sporadic type 3, when there is no associated pathology and normal blood gastrin. The gene discussed is GAST; the disease is multiple endocrine neoplasia type 1.