Diagrams for Dr. Saichin Wani at the University of Colorado Anschutz Medical Center showing the progression from normal to Barrett's Esophagus (a result of uncontrolled gastric reflux that increases the risk of developing esophageal cancer). The characteristic of Barrett's Esophagus is the growth of columnar epithelium from the stomach into the lower region of the esophagus, which should be comprised solely of squamous epithelial cells.