Interrelationship Among Helicobacter Pylori Infection, HTERTmRNA And P53 Protein Expressions In Gastric Mucosa Lesions

Background and objective: Helicobacter pylori (Hp)is the main etiological factor of chronic gastritis and is closely related to the occurrence of gastric cancer. Nowadays the model of normal mucosa—chronic superficial gastritis—chronic atrophic gastritis—intestinal metaplasia—dysplasia—gastric cancer suggested by Correa is generally accepted. Hp is thought to play an important part in the process of gastric carcinogenesis, but the definite mechanism remains unclear. The expression of telomerase activity and the mutation of p53 gene are thought to be widely associated with the occurrence of carcinomas, and the expression of human telomerase reverse transcriptase(hTERT) can reflect the telomerase activity in tissues and cells. The relationship among Hp, p53 protein, and hTERT expression has not been reported up to now. In this study, we investigated Hp infection, p53 protein and hTERTmRNA expressions of gastric mucosa in chronic superficial gastritis and precancerous gastric lesions , and analyzed the relationship among them in order to explore the mechanism of the evolution of gastric mucosa lesions induced by Hp infection .Methods: The biopsy specimens of gastric mucosa obtained from gastric endoscope were studied as the following: (1)The histopathology was examined with HE staining. (2)Hp infection was detected with rapid urease test and Giemsa staining. The presence of Hp infection was considered when two results were postive. (3)The expressions of p53 protein and hTERT mRNA were detected by immuhistochemial technique and RT-PCR respectively. Results: (1)Examination of Hp infection and histopathology: Of total 62 patients, 20 were CSG , 42 were precancerous lesions (18 chronic atrophic gastritis with intestinal metaplasia and 24 simple intestinal metaplasia). The rates of Hp infection were 55％(11/20)in CSG group and 57.1(24/42) in precancerous lesions guoup. There were no significant difference in the rates of Hp infection between two groups(p>0.05).(2)The expression rates of hTERTmRNA in different groups were as the following: 0.5％(1/20)in CSG group ; 9.1％(1/11)in CSG group with Hp infection; 0 in CSG group without Hp infection; 31.0％(13/42)in precancerous lesions group; 45.8％(11/24)in precancerous lesions group with Hp infection; and 11.1％(2/18)in precancerous lesions group without Hp infection. The expression rates of hTERTmRNA in precancerous lesions group were significantly higher than that in CSG group (p<0.05); and the rates in precancerous lesions group with Hp infectin were also significantly higher than in that without Hp infection(p<0.05). However, there were no significant difference between the expression rates in CSG group with Hp infection and without Hp infection(p>0.05). (3)The expression rates of p53 protein in different groups were as the following: 10％(2/20)in CSG group ; 18.2％(2/11)in CSG group with Hp infection; 0 in CSG group without Hp infection; 40.5％(17/42)in precancerous lesions group; 58.3％(14/24)in precancerous lesions group with Hp infection; and 16.7％(3/18)in precancerous lesions group without Hp infection. The expression rates of p53 protein in precancerous lesions group were significantly higher than that in CSG group (p<0.05); and the rates in precancerous lesions group with Hp infectin were also significantly higher than in that without Hp infection(p<0.05). However, there were no significant difference between the expression rates in CSG group with Hp infection and without Hp infection(p>0.05). (4)Interrelationship among Hp infection , p53 protein and hTERTmRNA expression: Of 24 precancerous lesions with Hp infection, 10 expressed both p53 protein and hTERTmRNA and 9 expressed neither of them at the same time, and the coincidence rates of both expression were 79.2％(19/24).There was a significant correlation between p53 protein and hTERTmRNA expression, and the correlation coeffecient was 0.608(p<0.05).Conclusions: (1)hTERT gene activation and p53 gene mutations play a part in the ear...