Pairwise mean comparisons found the percentages of MCM4 and MCM7 expression significantly increased from columnar cell metaplasia, Barrett's esophagus, low-grade dysplasia to high-grade dysplasia (P < .05), except for squamous mucosa versus columnar cell metaplasia and esophageal adenocarcinoma versus high-grade dysplasia (Table 1). The gene discussed is MCM7; the disease is Barrett esophagus.