Immunohistochemistry for CDX2 expression in non-goblet-cell Barrett's oesophagus

Interest has increased in CDX2 gene expression in oesophageal non-goblet-cell columnar metaplasia as recent investigations indicate such metaplasia possesses neoplastic potential. This study aims to assess expression of the transcription factor CDX2 specifically in non-goblet-cell cardia and fundic oesophageal metaplastic tissue, and to compare the location of CDX2 expression in non-goblet-cell specimens to that in goblet-cell specimens. A total of 43 patient specimens (20 fundic-type metaplasia, 42 cardia-type metaplasia and 18 intestinal metaplasia goblet cell-positive) were examined in this study. These were selected over six months from a patient database using the systematised nomenclature of human and veterinary medicine coding system (SNOMED). CDX2 was detected in patient specimens with an anti-CDX2 mouse monoclonal antibody. The types of mucosa in each specimen were confirmed by haematoxylin and eosin (H&E) staining. Fundic specimens were consistently CDX2-negative (0%). CDX2 expression was distinct in 55% of cardia and 100% of intestinal cases. Nearly all cardia-positive cases displayed focal expression (95.5%) and all intestinal cases displayed diffuse distribution of expression. Almost all cardia- and intestinal-positive specimens demonstrated epithelial expression (95.5% and 100%, respectively). The percentage of cardia-positive specimens with deep tissue expression was lower than in intestinal specimens (31.8% vs. 94.4%, respectively). This study confirms CDX2 as an early marker for Barrett's oesophagus in the absence of goblet cells as expression was noted in cardia metaplasia. CDX2 appears to induce the transformation of the normal oesophageal mucosa to cardia type, which then differentiates to an intestinal type under the influence of gastro-oesophageal reflux disease.