ALTERED CADHERIN AND CATENIN COMPLEXES IN THE BARRETTS ESOPHAGUS-DYSPLASIA-ADENOCARCINOMA SEQUENCE - CORRELATION WITH DISEASE PROGRESSION AND DEDIFFERENTIATION

The maintenance of adult tissue architecture is largely dependent on t he function of cadherins. E-cadherin is expressed in most epithelia, a lthough it may be coexpressed with P-cadherin in basal layers of strat ified epithelia. Adhesive function of cadherins relies on interactions with catenins, Many reports have characterized reduced expression of cadherins and catenins in tumors, including those of the gastrointesti nal tract, This study aimed to characterize expression of E- and P-cad herins, and the catenins, in the progression of Barrett's esophagus to adenocarcinoma. Immunohistochemical analysis and Western blotting wer e performed on paraffin-embedded and fresh-frozen tissue using antiser a to the selected cadherins and catenins, The results of this study ha ve shown inappropriate expression of cadherins and catenins in neoplas tic Barrett's mucosa, There was a significant reduction of E-cadherin expression as the Barrett's metaplasia-dysplasia-adenocarcinoma sequen ce progressed (P < 0.01), In contrast, P-cadherin, expressed in basal layers of squamous esophagus, was usually absent from Barrett's and dy splasia but was expressed in 17 of 24 carcinomas, especially at the ad vancing tumor edge. Reduced expression of catenins was also seen, but in some specimens, immunoreactivity was observed in neoplastic nuclei, suggesting mediation of a nuclear function such as transcriptional re gulation.