Figure 1

Immunohistochemical staining of USP9X expression in the progression from normal epithelium to ESCC. Paraffin-embedded tissue sections were stained using an immunoperoxidase method, as described in Materials and methods. Representative images (200×) are shown: A In normal esophageal epithelium, immunostaining for weak USP9X signal was found only in the basal layer. B In low grade intraepithelial neoplasia (left side), positive staining was observed in most of the heterogeneous cells from the basal layer to the granular layer of epithelium. The USP9X expression increased gradually in the transformation from low grade intraepithelial neoplasia to high grade intraepithelial neoplasia as carcinoma in situ in which the full-thickness epithelium showed diffuse immunoreactivity for USP9X (right side). C, D In ESCC, intense immunostaining for USP9X was presented in the cytoplasm of most of the cancer cells.