Progressive Suppression of Selenium Binding Protein 1 in Gastric Adenoma and Adenocarcinoma

ABSTRACT

BACKGROUND: Human selenium binding protein 1 (SELENBP1) is a protein that binds selenium as a cofactor. The decreased expression of SELENBP1 in several types of carcinomas and its association with a poor prognosis have previously been reported on. In this study, we evaluated the expression of SELENBP1 in low-grade and high-grade epithelial dysplasia/ adenomas and adenocarcinomas. METHODS: We analyzed 45 cases of low-grade epithelial dysplasia/adenomas, 42 cases of high-grade epithelial dysplasia/adenomas and 64 cases of adenocarcinomas and all of them were obtained from endoscopic mucosal resection or endoscopic submucosal dissection. We analyzed all of them for their SELENBP1 expression by immunohistochemistry. Eight triple-paired cases of gastric mucosa, adenoma and adenocarcinoma from the same patient were selected for RT-PCR analysis. RESULTS: There was a progressive decrease in the expression of SELENBP1 from the low-grade dysplasia/adenomas (42/45, 93%) to the high-grade dysplasia/adenomas (29/42, 69%) and finally to the adenocarcinomas (24/64, 37%), (p<0.001). The progressive decrease in the SELENBP1 expression was also evident in the eight paired cases that were analyzed by RT-PCR. CONCLUSIONS: Our findings demonstrate that the SELENBP1 expression is suppressed in gastric epithelial dysplasia/adenomas and adenocarcinomas. The suppression of SELENBP1 was significantly more frequent and severer in the adenocarcinomas than that in the low-grade dysplasia/ adenomas, and this implies that the suppression of SELENBP1 is a late event in gastric carcinogenesis.