MUC6 and chronic atrophic gastritis: To further verify the cellular origin of LCN2, we performed mIHC, and the results showed that there were a large number of cells co-staining with MUC6 and LCN2, and some cells co-staining with MUC5AC and LCN2 in both the gastric corpus with pyloric gland metaplasia samples and non-atrophic gastritis, indicating that LCN2 is expressed primarily in epithelial cells, and the increased LCN2 during pyloric gland metaplasia mainly originates from epithelial cells (Figure 5G).