Figure 4 Localisation of cyclooxygenases (COXs) and prostaglandin E synthase (PGES) in normal oesophagus and oesophagitis. COX‐1 expression was found in normal oesophageal epithelium (A), and inflammatory cells exhibited a reaction for COX‐1 in oesophagitis (B, C). There was no expression of COX‐2 in normal oesophagus (D) while epithelial cells of the basal layer and inflammatory cells in the lamina propria and submucosa exhibited a reaction for COX‐2 in oesophagitis (E). COX‐2 expression was found in mesenchymal cells (fibroblasts) in lamina propria (F). Cytosolic PGES expression in oesophagitis (G) was found in epithelial cells, endothelial cells (H), and some inflammatory cells (I). Microsomal PGES (mPGES)‐1 was not expressed in normal oesophagus (J) while epithelial cells and inflammatory and mesenchymal cells exhibited a reaction for it (K, L). mPGES‐2 expression was found in epithelial cells and inflammatory cells (M).