Yin Yang -1(YY1) is a member of the zinc finger factor GLI-Krüppel family. Objective:To investigate the gene expression and the function of YY1 in normal esophageal tissues and esophageal squamous carcinoma. Methods:The protein expression of YY1 in 88 esophageal squamous cell carcinomas,39 tumor adjacent tissues and 15 normal esophageal specimens was determined by immunohistochemistry (IHC). Proliferation and growth changes of esophageal squamous carcinoma cells were measured by MTT and colony formation. YY1 and p21 protein expressions were determined by Western blotting assays. TE-1 cell invasion and migration were determined by cell scratch experiment and Transwell invasive assays. Results:Compared to normal esophageal and tumor adjacent tissues,the expression of YY1 was significantly higher in esophageal squamous cell carcinomas. Furthermore,TE-1 cells overexpressing of YY1 significantly suppressed cell growth and downregulation of YY1 promoted cell growth. Meanwhile,a change of YY1 target gene p21 (p21WAF1/Cip1) was found. TE-1 cells overexpressing YY1 promoted cell invasion and migration. Conclusion:The expression of YY1 was significantly increased and regulated the growth,invasion and migration ability of esophageal squamous cells. Therefore,YY1 is expected to be a molecular marker in the diagnosis and development of esophageal squamous cell carcinoma,and also a potential target for gene therapy of esophagus cancer.