Smad4 expression in gastric adenoma and adenocarcinoma: Frequent loss of expression in diffuse type of gastric adenocarcinoma
J.Y. Kim1, D.Y. Park1, G.H. Kim2, K.U. Choi1, C.H. Lee1, G.Y. Huh1, M.Y. Sol1, G.A. Song2, T.Y. Jeon3, D.H. Kim3 and M.S. Sim3
1Department of Pathology, 2Department of Internal Medicine and 3Department of Surgery, College of Medicine, Pusan National University, Busan, Korea and Medical Research Institute, Pusan National University, Busan, Korea
Offprint requests to: Do Youn Park, M.D., PhD., Department of Pathology, College of Medicine, Pusan National University, Ami-1 Ga, Seo-Gu, Busan, Korea, 602-739. e-mail: pdy220@pusan.ac.kr
Summary. Smads are signal transducers for the members of the TGF-ß superfamily. Of these Smads, Smad4 is essential for TGF-ß signaling. The purpose of this study was to elucidate Smad4 expression and localization in 65 gastric adenomas, 49 intestinal-type and 39 diffuse type of gastric adenocarcinomas (including 12 cases of fresh frozen tissue) using Real-time RT-PCR and immunohistochemistry. Real-time RT-PCR showed that intestinal type gastric adenocarcinomas have higher Smad4 mRNA expression than diffuse type gastric adenocarcinomas. Immunohistochemical stain for Smad4 revealed that expression of Smad4 was significantly lower in diffuse-type gastric adenocarcinoma than intestinal-type gastric adenocarcinomas. Also, higher Smad4 protein expression in intestinal type gastric adenocarcinomas than overall gastric adenoma was noted. The rate of reduced Smad4 expression was higher in advanced gastric cancer than early gastric cancer. These results suggest that Smad4 might play different roles in human gastric carcinogenesis, especially between intestinal type and diffuse type of gastric adenocarcinoma. Histol Histopathol 20, 543-549 (2005).
Key words: Gastric adenoma, Gastric adenocarcinoma, Smad4, Reat-time RT-PCR, Immunohistochemistry
DOI: 10.14670/HH-20.543