Co-expression of LgR5 with Ki-67 in BE and OE-33 cells by immunofluorescence double staining. Images demonstrate a representative example of LgR5 co-expression with Ki-67 in early BE showing positivity for a small subset of LgR5+ cells with Ki-67+ (arrows). In contrast, a dominant population of proliferating (Ki-67+) Barrett cells were LgR5-, which may drive multi-step carcinogenesis (asterisks). Vice versa, most of LgR5+ Barrett cells were Ki-67- (asterisks). Proliferating LgR5+ OE-33 cells (arrows) are shown below (b). FITC green Fluoresceinisothiocyanat, Cy3 red, and DAPI 4',6-Diamidino-2- phenylindoldihydrochlorid blue. Top (a), Calibration bar represents 50 μm. Bottom, Calibration bar represents 25 μm (a and b). Case demonstrates area of magnification.