AIM:To observe the expression of Human telomerasereverse transcriptase(hTERT)in gastric carcinomas andprecanceresis lesions,to evaluate the immune state ofsuch patients,and to then study the clinical significanceof hTERT and immune state for the diagnosis,treat-ment and prognosis of gastric cancer.METHODS:In situ hybridization was used to detect theexpression of hTERT mRNA in 116 endoscopic of gas-tric mucosa.Analyzed tissue samples were as follows:30 cases of chronic superficial gastritis(CSG),44 ofprecancerosis lesions(including 27 of chronic atrophicgastritis,8 of adenomatous polyp and 9 of gastric ulcer)and 42 of gastric cancer(GC).In addition,the T lym-phocyte subsets(CD3~+,CD4~+,CD8~+,CD4~+/CD8~+)andnatural killer cells(NK)in peripheral blood were deter-mined by flow cytometric analysis(FCM)in 30 cases ofCSG,27 of precancerosis(chronic atrophic gastritis,CAG),and 42 of GC.The data were compared with thoseof normal control(NC).RESULTS:The detected positive rate of hTERT varied asfollows:86 %(36/42)in GC,36 %(16/44)inprecancerosis lesions and 0 %(0/30)in CSG.The ex-pression of hTERT mRNA was not associated with pa-tient gender,tumor location,macroscopic type,lymphnode metastasis,or degree of differentiation.It wasfound that the CD3~+,CD4~+of the CSG group were lowerthan that of NC(P<0.05).Meanwhile,the T lympho-cyte subsets(CD3~+,CD4~+,CD4~+/CD8~+ratio)and NK cellsof CAG were remarkably lower than that of NC and CSGgroups(P<0.05-0.01).Values of T cells and NK cells ofthe GC group were significantly abnormal when com-pared with the CAG group(P<0.05-0.01).Furthermore,with tumor progression,the function of T cells wasweakened gradually.CONCLUSION:The expression of telomerase may be acrucial step in gastric carcinogenesis and increasedhTERT mRNA may serve as a novel marker for diagno-sis of GC.The immune state of patients with GC andprecancerosis was somewhat depressed,which indi- cates the importance of cellular immunological assaysin cancer patients. AIM: To observe the expression of Human telomerase reverse transcriptase (hTERT) in gastric carcinomas and precancerous lesions, to evaluate the immune state ofsuch patients, and to then study the clinical significance of hTERT and immune state for the diagnosis, treat-ment and prognosis of gastric cancer . METHODS: In situ hybridization was used to detect the expression of hTERT mRNA in 116 endoscopic of gas-tric mucosa. Analyzed tissue samples were as follows: 30 cases of chronic superficial gastritis (CSG), 44 of precancer lesions (including 27 of chronic atrophic gastritis, 8 of adenomatous polyp and 9 of gastric ulcer and 42 of gastric cancer (GC) .In addition, the T lym-phocyte subsets (and CD3 ~ +, CD4 ~ +, CD8 ~ +, CD4 ~ + / CD8 ~ killer cells (NK) in peripheral blood were deter- mined by flow cytometric analysis (FCM) in 30 cases of CSG, 27 of precancerous (chronic atrophic gastritis, CAG), and 42 of GC.The data were compared with those of normal control ) .RESULTS: The detected positive rate of hTERT varied asf ollows: 86% (36/42) in GC, 36% (16/44) inprecancerosis lesions and 0% (0/30) in CSG.The ex-pression of hTERT mRNA was not associated with pa-tient gender, tumor location , macroscopic type, lymphnode metastasis, or degree of differentiation. It was found that the CD3 ~ +, CD4 ~ + of the CSG group were lowerthan that of NC (P <0.05) , CD4 ~ +, CD4 ~ + / CD8 + ratio) and NK cells of CAG were remarkably lower than that of NC and CSGgroups (P <0.05-0.01) .Values ​​of T cells and NK cells of the GC group were significantly abnormal when com -pared with the CAG group (P <0.05-0.01) .Furthermore, with tumor progression, the function of T cells was weakened gradually. CONCLUSION: The expression of telomerase may be acrucial step in gastric carcinogenesis and increasedhTERT mRNA may serve as a novel marker for diagno-sis of GC immune disease of patients with GC and precancerosis was somewhat depressed, which indi- cates the importance of cellular immunological assays in cancer patients.