| Background and objective: A close association between Helicobacter pylori(H.pylori) infection and gastric cancer has been affirmed. In 1994, the World Health Organization International Agency for Research on Cancer recognized H.pylori as a definite carcinogen for gastric cancer. However, the definite pathogenesis of H.pylori infection is as yet unclear. Telomerase activation is the important molecular basis for indefinite proliferation of malignant cells. Human telomerase RNA(hTR) and human telomerase catalytic subuint(hTERT) are two major components of telomerase. c-myc protein can increase the expression of hTERT, which makes telomerase activation. So far there have not been systematic study on the effect of H.pylori eradication on the telomerase-associated genes expression and the relationship between hTERT and c-myc protein in H.pylori-associated gastric carcinogenesis. We analyzed the expression of telomerase-associated genes and c-myc protein in pre- and post-H.pylori eradication gastric mucosa and H.pylori-associated gastric mucosal lesions and investigated the interation among H.pylori,telomerase-associated genes and c-myc protein in order to elucidate the possible mechanism of H.pylori infection in the pathogenesis and carcinogenesis.Methods: The expression of hTR,hTERT and c-myc protein were compared between before and after H.pylori eradication therapy or symptomatic treatment in 60 followed patients with chronic gastritis. hTR was determined by in situ RNA hybridization whereas hTERT and c-myc protein was detected by immunohistochemical staining(SP method). The expression of hTERT and c-myc protein in gastric mucosa cell were detected in the 175 cases. Analyzed gastric biopsy specimens were asfollows: 38 cases of chronic superficial gastritis(CSG, 20 H.pylori -positive cases, 18 H.pylori-negative cases), 25 chronic atrophic gastritis (CAG, 12 H.pylori-positive cases, 13 cases H.pylori- negative ), 48 intestinal metaplasia (IM, 19 H.pylori-positive cases, 29 H.pylori-negative cases), 14 dysplasia(DYS, 4 H.pylori- positive cases, 10 H.pylori-negative cases), 50 gastric cancer(GC, 18 H.pylori-positive cases, 32 H.pylori-negative cases). Results: ⑴The expression of hTERT and c-myc protein were all gradually increased from CSG to GC. In CSG,CAG,IM,DYS and GC, the expression of hTERT was 15.8%,36.0%,43.8%,50.0% and 86.0% and c-myc protein was 13.2%,36.0%,35.4%,50.0% and 80.0%, respectively. The expression of hTERT and c-myc protein were significantly higher in GC than that in GSC and precancerous lesions (P<0.05) and were also significantly higher in precancerous lesions than that in CSG (P<0.05). ⑵The positive rate of hTERT and c-myc protein were higher in precancerous lesions and GC with H.pylori infection than that without H.pylori infection. ⑶ The expression of hTERT and c-myc protein in H.pylori-positive GC were significantly higher than that in H.pylori-positive IM,CAG and CSG (P<0.05); and there were significant differences between H.pylori-positive precancerous lesions and CSG (P<0.05).The expression of hTERT and c-myc protein were significantly increased in H.pylori-negative GC, compared with H.pylori-negative precancerous lesions and CSG (P<0.05);but there were not significant differences between H.pylori-negative precancerous lesions and CSG (P<0.05). ⑷Before 60 followed patients received treatment, the expression of hTR,hTERT and c-myc protein were significantly higher in the H.pylori-positive group than that in the H.pylori-negative group. After H.pylori eradication ,the positive rate of hTR,hTERT and c-myc protein decreased significantly campared with itself before H.pylori eradication (P<0.05); in the persisting H.pylori infected and H.pylori-negative patients ,all the three parameters were not statistically decreased (P>0.05). ⑸ There were significant correlations between hTERT and hTR(rs 0.45,P<0.01),hTERT and c-myc protein (rs 0.474,P<0.01) in followed patients with chronic gastritis. The expression of hTERT and c-myc protein werefound to b... |
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