Objective To investigate the effect of human telomerase reverse transcriptase C27 polypeptide (hTERTC27) over-expression on orthotopic implanted tumor growth which induced by nasopharyngeal carcinoma cells C666-1 in vivo.Methods Stably transfected C666-1 cell lines were used to establish subcutaneously transplanted tumor mouse model.The tumor growth was observed and the tumor growth curve was made by measuring the volumes of tumors every day.HE staining was used to observe the change of histomorphology.The expressions of cleaved Caspase-3,Caspase-9,PARP,bax and bcl-2 were detected by Western blot analysis.Results The in vivo mouse model showed that over-expression of hTERTC27 significantly reduced tumor volume and tumor weight (P ＜ 0.05),and decreased the local muscle infiltration.Over-expression of hTERTC27 significantly up-regulated the expressions of cleaved Caspase-3,Caspase-9,PARP and bax (P ＜ 0.01),and down-regulated the expression of bcl-2 (P ＜ 0.01).Conclusion The results indicate that over-expression of hTERTC27 can obviously inhibit the growth of transplanted tumor in nude mice,which is possibly related to the regulation of bax and bcl-2 expression.