Fig. 1

Intensity of carbonic anhydrase IX (CA9) expression in esophageal adenocarcinoma with immunohistochemical staining. Samples were scored from 0 to 3: a, Negative (0, no stain or weak stain in <10 % cells). b, Weakly positive (1, weak stain in ≥ 10 % cells). c, Moderately positive (2, moderate stain in ≥ 10 % cells). d, strongly positive (3, strong stain in ≥ 10 % cells). CA9 expression was predominantly distributed in the tumor cell membrane