AIM： To investigate the relationship between Helicobacter pyiori（H pylori） infection, microsatellite instability and the expressions of the p53 in gastritis, intestinal metaplasia and gastric adenocarcinoma and to ...AIM： To investigate the relationship between Helicobacter pyiori（H pylori） infection, microsatellite instability and the expressions of the p53 in gastritis, intestinal metaplasia and gastric adenocarcinoma and to elucidate the mechanism of gastric carcinogenesis relating to Hpyloriinfection. METHODS： One hundred and eight endoscopic biopsies and gastric adenocarcinoma were available for the study including 33 cases of normal, 45 cases of gastritis, 30 cases of intestinal metaplasia, and 46 cases of gastric adenocardnoma. Peripheral blood samples of these patients were also collected. Hpyloriinfection and p53 expressions were detected by means of streptavidin-peroxidase （SP）immunohistochemical method. Microsatellite loci were studied by PCR-SSCP-CE using the markers BAT-26,D17S261, D3S1283, D2S123, and D3S1611. NSI was defined as the peak shift in the DNA of the gastric tissue compared with that of the peripheral blood samples. Based on the number of mutated MSI markers, specimens were charac-terized as high MSI （MSI-H） if they manifested instability at two or more markers, low MSI （MSI-L） if unstable at only one marker, and microsatellite stable （MSS） if they showed no instability at any marker.RESULTS： H pylori infection was detected in the samples of gastritis, intestinal metaptasia, and gastric adenocarcinoma and the infection frequencies were 84.4%, 76.7%, and 65.2%, respectively, whereas no Hpyloriinfection was detected in the samples of normal control. There was as ignificant difference in the infection rates between gastritis and carcinoma samples （P = 0.035）. No MSI was detected in gasbitis samples, one MSI-H and two MSI-L were detected among the 30 intestinal metaplasia samples, and 12 MSI-H and 3 MSI-L were detected in the 46 gastric carcinomas. In those gastric cardnomas, the MSI-H frequency in Hpylori-positive group was significantly higher than that in Hpylori-negative group. No p53 expression was detected in the normal and gastritis samples from dyspeptic patients. P53-positive immunohistochemical staining was detected in 13.3% of intestinal metaplasia samples and in 43.5% of gastric carcinoma samples. The levels of p53 in Hpylori-positive samples were higher than those in the negative group when the carcinoma samples were subdivided into H pylori-positive and -negative groups （P = 0.013）. Eight samples were detected with positive p53 expression out of the 11 MSI-H carcinomas with Hpyloriinfection and no p53 expression could be seen in the Hpylori-negativesamples.CONCLUSION： H py/ori affect the p53 pattern in gastric mucosa when MMR system fails to work. Mutations of the p53 gene seem to be an early event in gastric carcinogenesis.展开更多
文摘AIM： To investigate the relationship between Helicobacter pyiori（H pylori） infection, microsatellite instability and the expressions of the p53 in gastritis, intestinal metaplasia and gastric adenocarcinoma and to elucidate the mechanism of gastric carcinogenesis relating to Hpyloriinfection. METHODS： One hundred and eight endoscopic biopsies and gastric adenocarcinoma were available for the study including 33 cases of normal, 45 cases of gastritis, 30 cases of intestinal metaplasia, and 46 cases of gastric adenocardnoma. Peripheral blood samples of these patients were also collected. Hpyloriinfection and p53 expressions were detected by means of streptavidin-peroxidase （SP）immunohistochemical method. Microsatellite loci were studied by PCR-SSCP-CE using the markers BAT-26,D17S261, D3S1283, D2S123, and D3S1611. NSI was defined as the peak shift in the DNA of the gastric tissue compared with that of the peripheral blood samples. Based on the number of mutated MSI markers, specimens were charac-terized as high MSI （MSI-H） if they manifested instability at two or more markers, low MSI （MSI-L） if unstable at only one marker, and microsatellite stable （MSS） if they showed no instability at any marker.RESULTS： H pylori infection was detected in the samples of gastritis, intestinal metaptasia, and gastric adenocarcinoma and the infection frequencies were 84.4%, 76.7%, and 65.2%, respectively, whereas no Hpyloriinfection was detected in the samples of normal control. There was as ignificant difference in the infection rates between gastritis and carcinoma samples （P = 0.035）. No MSI was detected in gasbitis samples, one MSI-H and two MSI-L were detected among the 30 intestinal metaplasia samples, and 12 MSI-H and 3 MSI-L were detected in the 46 gastric carcinomas. In those gastric cardnomas, the MSI-H frequency in Hpylori-positive group was significantly higher than that in Hpylori-negative group. No p53 expression was detected in the normal and gastritis samples from dyspeptic patients. P53-positive immunohistochemical staining was detected in 13.3% of intestinal metaplasia samples and in 43.5% of gastric carcinoma samples. The levels of p53 in Hpylori-positive samples were higher than those in the negative group when the carcinoma samples were subdivided into H pylori-positive and -negative groups （P = 0.013）. Eight samples were detected with positive p53 expression out of the 11 MSI-H carcinomas with Hpyloriinfection and no p53 expression could be seen in the Hpylori-negativesamples.CONCLUSION： H py/ori affect the p53 pattern in gastric mucosa when MMR system fails to work. Mutations of the p53 gene seem to be an early event in gastric carcinogenesis.
