AIM:To detect the telomerase activity and c-Myc expressionin gastric diseases and to examine the relation betweenthese values and Helicobacter pylori(H pylori)as a riskfactor for gastric cancer.METHODS:One hundred and seventy-one gastric sampleswere studied to detect telomerase activity using atelomerase polymerase chain reaction enzyme linkedimmunosorbent assay(PCR-ELISA),and c-Myc expressionusing immunohistochemistry.RESULTS:The telomerase activity and c-Myc expression werehigher in cancers(87.69% and 61.54%)than in noncanceroustissues.They were higher in chronic atrophic gastritis withsevere intestinal metaplasia(52.38% and 47.62%)than inchronic atrophic gastritis with mild intestinal metaplasia(13.33% and 16.67%).In chronic atrophic gastritis withsevere intestinal metaplasia,the telomerase activity andc-Myc expression were higher in cases with Hpylori infection(67.86% and 67.86%)than in those without infection(21.43%and 7.14%).c-Myc expression was higher in gastric cancerwith H pylor/infection(77.27%)than in that withoutinfection(28.57%).The telomerase activity and c-Mycexpression were coordinately up-regulated in H pyloriinfected gastric cancer and chronic atrophic gastritis withsevere intestinal metaplasia.CONCLUSION:H pylori infection may influence bothtelomerase activity and c-Myc expression in gastric diseases,especially in chronic atrophic gastritis. AIM: To detect the telomerase activity and c-Myc expression in gastric diseases and to examine the relation betweenthese values ​​and Helicobacter pylori (H pylori) as a risk factor for gastric cancer. METHODS: One hundred and seventy-one gastric samples we studied to detect telomerase activity Using atelomerase polymerase chain reaction enzyme linked immunosorbent assay (PCR-ELISA), and c-Myc expression using immunohistochemistry .RESULTS: The telomerase activity and c-Myc expression werehigher in cancers (87.69% and 61.54%) than in noncanceroustissues.They were higher in chronic In chronic atrophic gastritis with severe intestinal metaplasia, the telomerase activity and c-Myc expression were higher in cases with Hpylori infection (52.38% and 47.62%) than inchronic atrophic gastritis with mild intestinal metaplasia (13.33% and 16.67% (67.86% and 67.86%) than in those without infection (21.43% and 7.14%). C-Myc expression was higher in gastric cancer with H pyl or telomerase activity (77.27%) than in that without infection (28.57%). The telomerase activity and c-Mycexpression were coordinately up-regulated in H pylori in gastric cancer and chronic atrophic gastritis with severe intestinal metaplasia. and c-Myc expression in gastric diseases, especially in chronic atrophic gastritis.