In gastric atrophy, caused by long-term H. pylori colonization, mature chief cells that are present at the base of glands are replaced by (metaplastic) cell types that co-express both the chief cell marker and markers of normal mucus-secreting cells residing in the gland neck, such as Trefoil Factor 2, TFF2 (spasmolytic polypeptide). The gene discussed is TFF2; the disease is chronic atrophic gastritis.