Mutations in beta-catenin and APC genes are uncommon in esophageal and esophagogastric junction adenocarcinomas

beta -catenin plays important roles in both intercellular adhesion and sign al transduction, Mutations in the beta -catenin or adenomatous polyposis co li (APC) gene can alter the degradation of beta -catenin and cause aberrant accumulation of beta -catenin result in increased transcription of target genes. The dysregulated APC/beta -catenin pathway has been recently discove red as an important mechanism of tumorigenesis in various cancers, but its role in esophageal adenocarcinomas is not clear. Therefore, we studied the beta -catenin gene mutation, allelic loss of chromosome 5q, and APC gene mu tation in esophageal and esophagogastric junction adenocarcinomas. Two (2%) somatic mutations in exon 3 of the beta -catenin gene, encompassing the re gion for glycogen synthase kinase-3 beta phosphorylation, were detected fro m 109 adenocarcinomas. Chromosomal allelic loss on 5q was frequent in 45.3% (44/97) of tumors. Only one missense mutation in the mutation cluster regi on of the APC gene was detected from 38 esophageal and esophagogastric junc tion adenocarcinomas with the 5q allelic loss. Our results based on partial screening mutational analyses indicate that mutations of APC/beta -catenin pathway, unlike in colorectal carcinoma, involve only a small subset of es ophageal and esophagogastric junction adenocarcinoma.