title: Variations in NAG-1 expression of human gastric carcinoma and normal gastric tissues.
abstract: Nonsteroidal anti-inflammatory drug-activated gene-1 (NAG-1), a member of the transforming growth factor β (TGF-β) superfamily, has been demonstrated to possess antitumorigenic and proapoptotic activities in gastric cancer cells. In the present study, the expression of NAG-1 was assessed in human gastric carcinoma, tumor-adjacent normal tissues and normal gastric mucosa, with the aim to investigate the role of NAG-1 in the carcinogenesis and development of gastric carcinoma. NAG-1 protein expression was evaluated using immunohistochemical staining, while the expression of NAG-1 mRNA was evaluated using reverse transcription-polymerase chain reaction. It was observed that adenocarcinoma tissues had a lower expression of NAG-1 than normal gastric tissues. Furthermore, moderately and well-differentiated adenocarcinoma tissues expressed more NAG-1 protein than the poorly differentiated adenocarcinoma tissues. The expression of NAG-1 protein in adenocarcinoma tissues did not correlate with tumor-node-metastasis staging, infiltration degree or tumor size. The NAG-1 mRNA expression in adenocarcinoma tissues was also lower than that in normal gastric tissues. In conclusion, NAG-1 was poorly expressed in adenocarcinoma tissues and inversely correlated with the degree of tumor differentiation. These results indicate that NAG-1 may have an anti-oncogenic function in the carcinogenesis and development of gastric carcinoma, and that its attenuated or absent expression may lead to gastric carcinogenesis.
authors.affiliation: Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China ; Department of Gastroenterology, Taihe Hospital, Hubei Medical University, Shiyan, Hubei 442000, P.R. China.
authors.forename: Gongli
authors.initials: G
authors.lastname: Yang
authors.affiliation: Department of Gastroenterology, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Qinhua
authors.initials: Q
authors.lastname: Tan
authors.affiliation: Department of Gastroenterology, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Department of Gastroenterology, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wei
authors.affiliation: Department of Gastroenterology, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Zhixin
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Gastroenterology, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Chengwei
authors.initials: C
authors.lastname: Tang
authors.affiliation: Department of Gastroenterology, Taihe Hospital, Hubei Medical University, Shiyan, Hubei 442000, P.R. China.
authors.forename: Shengbao
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Gastroenterology, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Chunhui
authors.initials: C
authors.lastname: Wang
keywords: gastric carcinoma; nonsteroidal anti-inflammatory drug activated gene-1