BACKGROUND/AIMS There has been no report regarding the regression of Barrett's esophagus (BE) by continuous treatment of proton pump inhibitor (PPI). The aim of this study was to determine the regression rate of BE by PPI and predictable markers related to regression.

METHODS Thirty-five patients diagnosed as BE were consecutively enrolled and most of them took continuous PPI. The 25 patients underwent endoscopic surveillance and received biopsy. If the specialized intestinal metaplasia (SIM) was lost at any point of surveillance and did not recur, the case was regarded as the regression group. The proportion of SIM was graded and the mucin phenotype was decided using immunohistochemistry for MUC2, MUC5AC and MUC6. To assess the cell proliferation indexes and the degree of intestinal maturation, immunohistochemistry for Ki67 and CDX2 were performed.

RESULTS The regression of BE occurred in the 11 (44%) patients. The clinical and demographic factors showed no difference between the regression (n = 11) and persistence group (n = 14). The lower grade of SIM (P < 0.001) and gastric predominant mucin phenotype (P = 0.018) were more frequent, and the number of Ki67 positive cell per gland (P = 0.008) and the mean extent of CDX2 (P = 0.022) were lower in the regression group than in the persistence group.

CONCLUSIONS The regression of BE by PPI treatment was frequent in Korea. The immunohistochemical detection of mucin phenotype, grade of SIM, Ki67 and CDX2 expression in Barrett's mucosa could be useful as a predictable marker for regression of SIM in BE.