Background: Data from previous studies on intestinal metaplasia at the gastroesophageal junction have been conflicting, which makes the diagnosis of Barrett's esophagus less obvious. This may partly be due to the lack of a reliable classification of the Z-line appearance. We previously proposed such a classification (the ZAP classification) that was shown to correlate with the prevalence of intestinal metaplasia. The use of different immunohistochemical techniques has increased in the study of intestinal metaplasia. In the present study our aim was to 1) evaluate the impact of different antibodies, namely cytokeratin (CK) 7, 13, and 20, CaCO3/73, and FBB2/29, in order to differentiate between Barrett's esophagus and cardia intestinal metaplasia, and 2) explore the staining patterns in different ZAP grades.
Methods: Thirty-nine specimens with intestinal metaplasia were compared--9 from Barrett's esophagus, 6 from cardia, and 24 from the Z-line. The Z-line specimens were evaluated with respect to ZAP grade.
Results: No differences were encountered regarding staining patterns for CK13 and CaCO3/73 in Barrett's esophagus and cardia. The staining pattern of CK7/20 was significantly different between Barrett's esophagus and cardia. CK7/20 showed a rising frequency of Barrett's esophagus staining pattern with rising ZAP grade.
Conclusion: CK7/20 is a feasible marker for Barrett's esophagus. Intestinal metaplasia in different ZAP grades differs regarding expression of immunohistochemical markers.