SOX9 and infectious otitis media: Immunostaining-positive cells of β-catenin (green; Figure 5A), Sox9 (red; Figure 5B), Ki67 (green; Figure 5C), cyclin D1 (red; Figure 5D), or CDK4 (green; Figure 5E) were observed in the uni-cryptal neoplastic lesions of the AOM/DSS mice using DAPI nuclear staining (blue).