Expression of nuclear factor-kappa B and target genes in gastric precancerous lesions and adenocarcinoma： Association with Helicobactor pylori cagA （＋） infection
摘要
AIM:To examine the expression of nuclear factor kappaB (NF-κB) and its target genes in intestinal metaplasia (IM),dysplasia (DYS) and gastric carcinoma (GC) infected with Helicobacter pylori (H pylori) and to investigate the mechanism underlying Hpyloricytotoxin associated gene A(cag A) infection leading to gastric adenocarcinoma.METHODS: Expressions of NF-κB/p65 and its target genes:c-myc, cyclinD1 and bcl-xl were immunohistochemically examined in 289 cases of gastric biopsy and resection specimens from patients with IM, DYS and GC infected with H pylori. H pylori in the above mentioned tissues was detected by Warthin-Starry stain and rapid urease tests.IgG antibody to cagA in sera of the patients was measured by ELISA.RESULTS:The positive rates of NF-κB/p65 were significantly higher in groups with cagA of IMI-Ⅱ(28/33), IM III(48/52),DYSI(27/31), DY5 Ⅱ-Ⅲ(28/32), GC(35/40) than in groups without cagA of IMI-Ⅱ(4/17), IMⅢ(3/20), DYSI(3/20),DYSⅡ-Ⅲ(6/21), GC(10/23). The expressions of c-myc,cyclinD1, and bcl-xl were significantly higher in groups with cagA of IM Ⅲ(47/52, 49/52, 46/52), DYSⅡ-Ⅲ(29/32, 26/32,25/32) than in groups without cagA of IM Ⅲ(8/20, 7/20,5/20), DYSⅡ-Ⅲ(10/21, 8/21, 3/21), which were in conformity with the expression of NF-κB in IM Ⅲ, and DYSⅡ-Ⅲ. Asignificantly higher expression level of NF-κB/p65, c-myc,cyclinD1 and bcl-xl was detected in intestinal type GC(27/28,18/28, 22/28, 24/28) than in diffuse type GC(8/12, 3/12,3/12, 6/12), respectively.CONCLUSION: There may be two different molecular mechanisms in the occurrence of intestinal and diffuse type gastric carcinomas. Intestinal type gastric carcinoma is strongly associated with high expression of c-myc, cyclinD1 and bcl-xl through NF-κB/p65 activated by Hpylori cagA.Inhibiting the activity of NF-κB is an effective and promising way to prevent intestinal type gastric carcinoma.