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Fig. 4. An overall model of cellular organization in the oesophageal epithelium.
The IBL cells constitute the epithelial stem cell compartment (red). IBL cells
proliferate infrequently and asymmetrically. Transit amplifying cells reside
in the epibasal layers (gray). PBL cells (green) are intermediate in behavior
between IBL and epibasal cells (see text). Differentiated squames are shown in
yellow. PBL cells probably migrate off the tips of the oesophageal papillae as
suprabasal integrin expression is a consistent finding at this site
(Seery and Watt, 2000). This
phenomenon is seen in the epidermis when rapidly proliferating cells migrate
out of the basal layer (Rikimura et al.,
1997). [Figure reprinted from
(Seery and Watt, 2000) with
permission from Elsevier Science].