Lesions Of The Esophagogastric Junction:Expressions And Effects Of APC And β-CATENIN

Background:In recent years, the prevalence of distal gastric cancer in Western developed countries continue to decline, while the incidence of adenocarcinoma of the esophagogastric junction (AEG) has increased annually. The long-term survival of AEG is poor and depends on the possibility of performing a complete surgical excision and the absence of lymph node involvement. At presence, there is few studies on the molecular mechanism of its pathogenesis, and most scholars believe that intestinal metaplasia(M) is one of the risk factors of AEG. The intestinal epithelium may have two sources:intestinal metaplasia at Barrett’s esophagus(BEM) and at cardia(CM), whether they belong to the same disease and have the same risk for development of adenocarcinoma, there is still a lot of controversy.Purpose:To study the expressions of APC and β-Catenin in lesions of esophagogastric junction, and to investigate the correlation of the intestinal metaplasia between at Barrett’s esophagus(BE) and at cardia, and the evolution of adenocarcinoma of the esophagogastric junction.Methods: The immunochemistry method was used to detect APC and β-Catenin proteins expressions in33BEM specimens,36CM specimens, and42AEG specimens (Poorly differentiated27; Moderated differentiated8; Highly differentiated7).Results:APC located predominantly in the cytoplasm, and the expression level in the AEG group was weaker than the BEM and the CM group; β-Catenin in the BEM and the CM group, almost all expressed in the cell membrane, while in the AEG group, were expressed partly in the nucleus and cytoplasm. The positive rates of APC expression in the BEM, the CM and the AEG group, were87.9%,83.3%,57.1%, respectively; and β-Catenin were93.9%,88.9%,85.7%, respectively. The expression of APC was correlated well with the pathological grade of lesions (M--AEG Poorly differentiated-Moderated differentiated-Highly differentiated), while β-Catenin was not correlated completely.Conclusions:1. APC protein may be involved in the development of the intestinal metaplasia-adenocarcinoma in the esophagogastric junction, and its expression levels decrease with increasing degree of malignancy.2. The expressions of β-Catenin in the BEM group, CM group and AEG group are different, and its ectopic expression may play a role in the development of AEG.3. The positive rates of APC and β-catenin in the BEM group and CM group are of no significant difference, and there is a similar expression characteristics of APC and β-catenin between the two intestinal metaplasia correlating with the AEG, the BEM and CM may be the same kind of lesion.4. BEM and CM are risk factors of the AEG.