The Role of the Helicobacter pylori CagA Gene in Gastric Cancer Tissue of Koreans

Lee, Han Chu; Yi, Sun Young; Jung, Sung Ae; Moon, Il Hwan; Jung, Hye Kyung; Kim, Doe Young

Abstract

BACKGROUND AND AIMS
To further understand the relationship between the cagA gene and gastric cancer, the positive rates of the cagA gene in cancer and non-cancer tissues were investigated separately in patients with gastric cancer.
METHODS
The cagA gene was detected by PCR and the ureC gene was analyzed as a positive control for the presence of Helicobacter pylori. Each of two endoscopic biopsies were obtained from cancer and non-cancer tissues of 41 patients with gastric cancer.
RESULTS
1) The positive rate of the cagA gene in cancer tissues was 29.3% (12/41), which was significantly lower than that in non-cancer tissues (63.4%). 2) Twelve (29.3%) out of 41 were positive for the cagA gene in both cancer and non-cancer tissues, 14 were positive in only non-cancer tissues, none were positive in only cancer tissues, and 15 (36.6%) were negative in both sites. 3) The ureC gene was negative in cancer tissue in 12 (85.7%) among 14 cases who were cagA gene negative in the cancer tissue but positive in the non-cancer tissue. 4) There was no difference in the positive rate of the cagA gene according to age, stage, site, and pathologic cell type.
CONCLUSIONS
These findings indicate that the positive rate of the cagA gene in cancer tissue was lower than that in non-cancer tissues and this might be related to a low infection rate of H. pylori in cancer tissue rather than the presence of cagA negative H. pylori in cancer tissues.