Abstract: Objective：To evaluate Alarelin on human endometrial carcinoma HEC-1-B cells in nude mice and its mechanism. Methods：Establishment of endometrial carcinoma xenografts in nude mice，according to the nude volume，32 nude mice were randomly divided into 4 groups（n=8）：control group, Alarelin groups （20，40，80 μg/kg，respectively）. The growth curves of xenografts in nude mice were drawn and inhibition rates were measured. The morphological features were detected by hematoxylin and eosinstaining. The protein expression levels of DEDD were measured by immunohisto chemistry. Results：The growth curve showed that tumor volume in nude mice treated with Alarelin was smaller than that of control group. The rate of tumor inhibition in low，medium and high-dose Alarelin group were 12.65%，27.38% and 35.43％，all with a statistically significant difference（P＜0.05）. HE staining showed that tumor cells arranged in dense，with clear atypia，large nuclei，stained emitotic more ，less interstitial in control group. Compared with control group，tumor cell morphology，cell arrangement sparse，showing large unstructured necrosis，tumor cell nuclei stained pyknotic more mitotic less in different dose group. Results of immunohistochemical showed that in the gray values of DEDD protein expression in low，medium and high dose groups were 156.20±5.10，142.85±7.27 and 113.65±4.38 respectively，they were significantly lower than the control group（171.75±8.21，all P＜0.001）. Conclusions：Alarelin can effectively inhibit the growth of tumor，the mechanism may be correlated with increasing expressions of DEDD.

Key words: Endometrial neoplasms, Gonadotropin-releasing hormone, Neoplasm transplantation, Mice, nude