EMX2 and esophageal squamous cell carcinoma: All four EMX2-transfected ESCC clones of 106 cells and one clone (EMX2-KYSE170-1) of 103 cells developed tumors, while none of the two EMX2-absent control clones of 106 cells (EMX2/GAPDH = 0), which were generated by transfection of control vector into the corresponding two ESCC cell lines, formed tumors at this time point (Figure S2).