The incidence of adenocarcinoma of the esophagus has been increasing in developing countries over the last three decades and probably reflects a genuine increase in the incidence of its recognized precursor lesion , Barrett's metaplasia. Despite advances in multimodality therapy , the prognosis for invasive esophageal adenocarcinoma is poor. An improved understanding of the molecular biology of this disease may allow improved diagnosis , therapy , and prognosis. We focus on recent developments in the molecular and cell biology of Barrett's metaplasia , a heterogeneous lesion affecting the transitional zone of the gastro-esophageal junction whose associated molecular alterations may vary both in nature and temporally. Early premalignant clones produce biological and genetic heterogeneity as seen by multiple p53 mutations , p16 mutations , aneuploidy , and abnormal methylation resulting in stepwise changes in differentiation , proliferation , and apoptosis , allowing disease progression under selective pressure. Abnormalities in expression of growth factors of the epidermal growth factor family and cell adhesion molecules, especially cadherin/catenin complexes , may occur early in invasion. Exploitation of these molecular events may lead to a more appropriate diagnosis and understanding of these lesions in the future. (Am J Pathol 1999, 154:965-973)

Background-Evidence exists for a role

Duodenal ulcers are associated with gastric metaplasia in the duodenum, both at the ulcer margin and at more distant sites in the duodenal bulb. pS2 and human spasmolytic polypeptide (hSP) are secretory peptides expressed in gastric epithelial ceils and in gastric metaplasia. As these peptides may be important in ulcer healing, this study investigated the possibility that the expression ofpS2 and hSP is increased in gastric metaplasia at the margin ofduodenal ulcers. (SEM), 20.6 (3.3) v 9.5 (3.0); p<0.001). There was a trend towards greater hSP staining at the ulcer margin but this did not achieve statistical significance. These findings support the putative role of pS2 and possible hSP in mucosal healing and providy further evidence for an autocrine 'ulcer-gastric metaplasia-repair' loop involving these trefoil peptides.

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Campylobacterpylori is a gram negative spiral bacterium that produces a powerful urease that splits urea with the production ofammonia. By neutralising intragastric pH with ammonia C pylori is able to colonise the stomach and survive conditions unsuitable for other bacteria. We present a patient who illustrates the relation between C pylori and plasma gastrin concentration and whose duodenal ulcer disease was healed only after treatment was aimed at eradication of C pylon.

The Apc(MIN/+) mouse is a well-characterised model of intestinal tumourigenesis in which animals develop macroscopically detectable adenomas. However, most of the adenomas are formed in the small intestine and resolution of events in the colon, the most relevant site for human disease, is limited. Inducing colitis with dextran sodium sulphate (DSS) can selectively enhance the development of lesions in the colon. We demonstrated that a DSS pre-treatment is well tolerated and effective at inducing colon adenomas in an Apc(MIN/+) mouse model. We then investigated the effect of inhibiting vascular endothelial growth factor (VEGFR)- and epidermal growth factor receptor (EGFR)-dependent signalling pathways on the development of adenomas induced in DSS-pretreated (DSS/Apc(MIN/+)) or non-DSS-pretreated (Apc(MIN/+)) mice using vandetanib (ZD6474), a potent and selective inhibitor of VEGFR and EGFR tyrosine kinase activity. Eight-week old Apc(MIN/+) mice were given either drinking water or 1.8% DSS and then vandetanib (ZD6474) (50 mg/kg/day) or vehicle by oral gavage for 28 days and sacrificed 24 h after the last dose and assessed for adenoma formation in the intestines. DSS pre-treatment was well tolerated and significantly enhanced formation of adenomas in the colon of control Apc(MIN/+) mice. Vandetanib treatment significantly reduced adenoma formation in the small intestine by 68% (P=0.001) and the colon by 77% (from 13.8 to 3.1, P=0.01) of DSS-pretreated Apc(MIN/+) mice. In the Apc(MIN/+) group, vandetanib also reduced the mean number of adenomas in the small intestine by 76% (P<0.001) and in the colon by 60% (from 3.9 to 1.5, P=0.1). DSS-pre-treatment increased the resolution of the model, allowing us to confirm statistically significant effects of vandetanib on the development and growth of colon adenomas in the Apc(MIN/+) mouse. Moreover these preclinical data provide a rationale for studying the effects of vandetanib in early stages of intestinal cancer in the clinic.

Cell production rates were measured in 19 cases of rectal carcinoma and in 11 cases of gastric carcinoma using a stathmokinetic technique. These measurements were compared with results from normal rectal and gastric mucosa. It was found that most of the cases of rectal cancer were proliferating more slowly than morphologically normal rectal mucosa. This was true for the majority of gastric cancers, but a small proportion appeared to be proliferating more rapidly. These results are discussed with their relevance to appropriate therapy.