NOTCH1 and esophageal squamous cell carcinoma: To dissect further the mechanistic role of Notch1 in the generation and maintenance of ESCC tumor cells with mesenchymal features, we utilized the genetically engineered transformed esophageal cell line EPC2T (EPC2-hTERT-EGFR-p53R175H-cyclin D1), comprising discrete CD44L and CD44H subpopulations with epithelial and mesenchymal traits, respectively31 (Supplementary Fig. 3a).