Figure 1.

4NQO-induced neoplastic changes in esophagus tissues of mice at different time intervals. Control, normal; ESSH, simple hyperplasia; IEN, intraepithelial neoplasia; ESCC, esophageal squamous cell carcinoma. (A) Scheme for the treatment paradigm. C57BL/6 mice were randomized into two groups and fed with water or 4NQO (100 μg/mL) in drinking water for 16 weeks, after which all mice were given deionized water until week 28. Mice were sacrificed at different time points of 4NQO treatment at 0, 4, 8, 12, 16, 20, and 28 weeks to observe the different pathological stages of carcinogenesis in mice. The histopathological assessment, immunohistochemistry, and WES of esophageal tissues were performed after 4, 16, and 28 weeks. (B) Representative images of esophageal lesions for each stage. (C,D) Histological analysis and ki-67 staining of mice’s normal esophagus and ESCC esophagus for each stage. (Magnification, ×400; scale bar = 50 μm).