POU5F1 and esophageal squamous cell carcinoma: To further investigate the molecular mechanism of OCT4-involved cell apoptosis and cell cycle arrest in Eca109 and TE1 cells, we found that the ESCC cells expressed lower levels of OCT4 and Survivin protein after transfected with OCT4-shRNA, but Sur-shRNA only down-regulated Survivin expression and there was no change in OCT4 expression level.