(A) High correlation (r=0.97) of SOX15 and KRT5 mRNAs in normal esophagus, BE, and EAC, validating KRT5 as a proxy for SOX15 and other stratified epithelium-specific genes. (C-D) Representative immunohistochemistry for KRT5 (red, a surrogate marker for SOX15 and other squamous-specific gene products) and CDX2 (brown, a representative intestine-specific marker) in two separate cases (C and D) of human EAC. High KRT5 expression is evident, with almost mutually exclusive distribution of KRT5 (++ to +++) and CDX2 (+++ to ++++) in the same malignant glands. Original magnifications: Top, 200X; Bottom, 400X. (E) Absence of KRT5 immunostaining in areas of BE. Adjoining areas of normal stratified epithelium provide a positive control and contrast.