Gastric Cancer
Copyright ©2008 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Jun 28, 2008; 14(24): 3804-3811
Published online Jun 28, 2008. doi: 10.3748/wjg.14.3804
PCR-SSCP-DNA sequencing method in detecting PTEN gene mutation and its significance in human gastric cancer
Chuan-Yong Guo, Xuan-Fu Xu, Jian-Ye Wu, Shu-Fang Liu
Chuan-Yong Guo, Xuan-Fu Xu, Jian-Ye Wu, Shu-Fang Liu, Department of Gastroenterology, Tenth People’s Hospital of Tongji University, Shanghai 200072, China
Correspondence to: Chuan-Yong Guo, Professor, Depart-ment of Gastroenterology, Tenth people’s Hospital of Tongji University, Shanghai 200072, China. guochuanyong@hotmail.com
Telephone: +86-21-66302535
Fax: +86-21-66303983
Received: October 25, 2007
Revised: May 8, 2008
Accepted: May 15, 2008
Published online: June 28, 2008
Abstract

AIM: To discuss the possible effect of PTEN gene mutations on occurrence and development of gastric cancer.

METHODS: Fifty-three gastric cancer specimens were selected to probe PTEN gene mutations in genome of gastric cancer and paracancerous tissues using PCR-SSCP-DNA sequencing method based on microdissection and to observe the protein expression by immunohistochemistry technique.

RESULTS: PCR-SSCP-DNA sequencing indicated that 4 kinds of mutation sites were found in 5 of 53 gastric cancer specimens. One kind of mutation was found in exons. AA-TCC mutation was located at 40bp upstream of 3’ lateral exon 7 (115946 AA-TCC). Such mutations led to terminator formation in the 297th codon of the PTEN gene. The other 3 kinds of mutation were found in introns, including a G-C point mutation at 91 bp upstream of 5’ lateral exon 5(90896 G-C), a T-G point mutation at 24 bp upstream of 5’ lateral exon 5 (90963 T-G), and a single base A mutation at 7 bp upstream of 5’ lateral exon 5 (90980 A del). The PTEN protein expression in gastric cancer and paracancerous tissues detected using immunohistochemistry technique indicated that the total positive rate of PTEN protein expression was 66% in gastric cancer tissue, which was significantly lower than that (100%) in paracancerous tissues (P < 0.005).

CONCLUSION: PTEN gene mutation and expression may play an important role in the occurrence and development of gastric cancer.

Keywords: Gastric cancer; PTEN gene; PCR-SSCP; DNA sequencing; Mutation