CTSG and chronic atrophic gastritis: Campana et al. evaluated Cg A plasma levels in patients with several phenotypes of endocrine tumor and at different stages of the disease, comparing with healthy participants and patients who have chronic atrophic gastritis (CAG), with and without enterochromaffin cell-like (ECL) hyperplasia while Arnold et al. evaluated Cg A distribution in patients with NET and chronic atrophic gastritis (Figure 1) [65, 66].