CA9 and esophageal adenocarcinoma: Of the tissue microarray cases, 90 % (101/112) esophageal adenocarcinoma, 94 % (16/17) high-grade dysplasia, 85 % (17/20) low-grade dysplasia, 74 % (20/27) Barrett esophagus, 83 % (48/58) columnar cell metaplasia, 9 % (2/23) squamous cell carcinoma, and 0 % (0/62) squamous epithelium had high CA9 expression (Table 1, Fig. 1, 2 and 3).