An average BrdU+Ki67+ cell density was about 5 times higher for P22-25 than P19-22 and over 2 times higher for P22-25 than P25-28 in BE mice (Fig 1I; Tukey-Kramer post hoc test, p = 0.0034 for P19-22 vs. P22-25, p = 0.015 for P22-25 vs. P25-28). This evidence concerns the gene MKI67 and Barrett esophagus.