TCF4 and Fuchs endothelial corneal dystrophy: We first investigated TCF4 expression by western blot analysis on CEC lines derived from normal healthy (HCEC-21T)41 or FECD patients (FECD-54F, FECD-61M, FECD-74F)17, and observed elevated TCF4 protein expression in FECD CECs (Fig. 1B, left panel, Supplemental Fig. S1A)).