UBE2S and intraepithelial neoplasia: The IHC method was carried out to observe whether there were differences in the expressions of UBE2S, HIF‐1α, and FOXM1 in low‐grade intraepithelial neoplasia (LIN), high‐grade intraepithelial neoplasia (HIN), and the normal epithelial tissues of the esophagus.