The gland pattern, including the basal TFF2+/MUC6+ cells, are preserved in dysplasia, with dysplastic cells confined to the upper part of the gland; in gastric carcinoma, the dysplastic cells may originate in the deep pit or isthmus of the gastric gland:29 in Barrett's oesophagus, the dysplastic part of the gland is clonal for p16 mutations even when the surface cells lack dysplastic features.30 It is not yet known if this is true also for the basal TFF2+/MUC6+ basal mucous cells. This evidence concerns the gene TFF2 and dysplasia.