Predominant stromal cell COX-2 localisation during the pre-malignant phase followed by neoplastic epithelial cell COX-2 expression during malignant progression has been observed in other parts of the gastrointestinal tract, in which chronic inflammation predisposes to carcinogenesis, such as reflux oesophagitis/Barrett’s oesophagus53 and Helicobacter pylori-associated chronic gastritis54. Here, PTGS2 is linked to peptic esophagitis.