Abnormal expression of growth regulatory factors in Barrett's oesophagus.

1. In order to assess potential abnormalities in the control of mucosal proliferation, 30 patients with Barrett's oesophagus were studied in order to evaluate the presence and distribution of epidermal growth factor, transforming growth factor-alpha and epidermal growth factor receptor to determine the Ki-67 labelling index in the affected oesophageal mucosa. Serial sections were analysed immunohistochemically. Ten of the patients had adenocarcinoma in the Barrett's mucosa and the other 20 had differing histological types of Barrett's mucosa (10, intestinal-type; 10, fundic- or cardiac-type). 2. The expression of transforming growth factor-alpha, epidermal growth factor and epidermal growth factor receptor was increased and the Ki-67 labelling index was higher in Barrett's mucosa compared with normal gastric mucosa. The 'intestinal-type' of Barrett's mucosa had the greatest expression of transforming growth factor-alpha, epidermal growth factor receptor and the highest Ki-67 labelling index compared with the other types of Barrett's metaplasia. Five cases of 'intestinal-type' Barrett's metaplasia had especially high Ki-67 labelling indices and these patients over-expressed both transforming growth factor-alpha and epidermal growth factor receptor. The patients with adenocarcinomas in the Barrett's mucosa also over-expressed transforming growth factor-alpha and epidermal growth factor receptor, but not epidermal growth factor, compared with normal gastric mucosa. 3. In conclusion, both normal gastric mucosa and Barrett's mucosa have potential autocrine growth regulatory mechanisms, but Barrett's mucosa has increased expression of both of the measured ligands and of the epidermal growth factor receptor.