POU5F1 and esophageal squamous cell carcinoma: Intriguingly, the enhanced TWIST1 gene expression in ESCC cell lines KYSE-30 and YM-1 resulted in the significant overexpression of OCT4 (stem cell-associate transcription factor), MAGEA4, and NY-ESO1 (testicular cancer antigens), N-cadherin, Occluding, ZEB2, Fibronectin, and Vimentin (EMT markers), suggesting a key relation between EMT and CSC formation in esophageal tumor cells [12,13,16].