Thus, we supposed USP9X correlated with the progression of ESCC and up regulation of USP9X might be a late event in the multistep pathogenesis of ESCC, because 55.3% of low grade intraepithelial neoplasia were not detected with USP9X expression, whereas 77.2% of high grade intraepithelial neoplasia had positive expression of USP9X (P = 0.012). This evidence concerns the gene USP9X and intraepithelial neoplasia.