Quantification of CYP26A1 expression in cervical squamous intraepithelial neoplasia. (A–D) The color images of each representative field (e.g., Figure 1D, F, H, and J) were transformed into grayscale images and subsequently converted to binary images according to the threshold value. (E and F) Quantification of positive signals. Horizontal bars represent the mean values. P < 0.05 versus quantification of stained tissues from normal epithelium (a) or epithelium with mild (b), moderate (c), and severe (d) dysplasia, as well as those from low-grade squamous intraepithelial lesions (e).