Abstract: Objective：To investigate the aberrant methylation and the expression of Hedgehog Interacting Protein （HHIP） gene in endometrial carcinoma，and to explore the possible relationship between the methylation of the gene and the expression of the gene and their effect on the carcinogenesis and the proliferation of the endometrial carcinoma. Methods：The promoter methylation status of HHIP gene was tested by methylation-specific PCR in 20 normal endometrium tissus and 30 endometrial carcinoma tissus. The expression of HHIP was studied by histochemistry in 20 cases of normal endometrium and 30 cases of endometrial carcinoma.The correlation between the methylation status and endometrial carcinoma ，the correlation between the HHIP silencing and endometrial carcinoma as well as the correlation between the methylation status and the silencing of HHIP were tested by SPSS 13.0. Results：The frequencies of hepermethylation of HHIP in normal endometrium tissues were 0%（0/20），while the frequencies of heper-methylation of HHIP in endometrial carcinoma tissue were 40%（12/30）. The methylation rate in endometrial carcinoma tissue was higher than the methylation rate in normal endometrium tissue. All the normal endometrium tissues showed positive staining pattern of HHIP protein（20/20）. 40%（8/20） of endometrial carcinoma
tissues showed positive staining pattern of HHIP protein. In endometrial cancer， the HHIP protein silencing was easier to be found than in the normal endometrium tissue.The hepermethylation of HHIP gene was not related with the expression of HHIP protein（P＞0.05）. Conclusions：HHIP is related to the occurrence and the development of the endometrial carcinoma. The methylation rate in endometrial carcinoma tissue is higher than that in normal endometrium tissue. In endometrial cancer， the HHIP protein silencing is easier to be found than in the normal endometrium tissue. The methylation of the HHIP gene promoter may be related to the silencing of the expression of the protein to some extent，and it may be involved in the occurrence of the endometrial carcinoma. However， methylation may not be the only reason for the silencing of the expression of HHIP， and other mechanisms remain to be revealed.

Key words: Endometrial neoplasms, Adenocarcinoma, Methylation, Immunohistochemistry, Polymerase chain reaction