MKI67 and Barrett esophagus: Similarly, Feith et al. investigating the malignant degeneration of Barrett's esophagus showed that there was a low expression of Ki-67 in normal squamous epithelium of the esophagus (only 20.4 ± 6.4% of cells were Ki-67-positive) compared to columnar metaplasia (34.9 ± 11.1%), dysplasia (44.8 ± 8.9%), and invasive carcinoma (60.8 ± 17.9%) [38].