Abstract: Expression and Significance of Human Epididymis Gene Product 4 in Tissue and Serum ofPatients with Endometrial CancerCaihong YANG1, Yonghui XU2, Xueyu ZHANG1Correspondence to: Xueyu ZHANG, E-mail: zhxueyu@163.com1Department of Gynecology, The Affiliated Hospital of Ningxia Medical University, Yinchuan 750004, China2Department of Pathology, The Affiliated Hospital of Ningxia Medical University, Yinchuan 750004, ChinaThis study was supported by funds from 2010 Torch-Plan Projects of Ningxia Hui Autonomous Region (No. Ningkejizi2010168)Abstract Objective: To explore expression and significance of human epididymis protein 4 ( HE4 ) in tissue and serum of pa-tients with endometrial cancer. Methods: Immunohistochemistry was used to detect the expression of HE4 protein in the tissue of thenormal control ( NC ) group with normal proliferative endometrium ( n = 20 ), the endometrial hyperplasia ( EnHy ) group ( n = 19 )and endometrial carcinoma ( EnCa ) group ( n = 31 ). Quantitative analysis of the detection was conducted by the pro-plus 6.0 profes-sional image analysis software, and the target integral optical density ( IOD ) was used for the judgement parameter. The enzyme-linkedimmuno-sorbent assay ( ELISA ) technique was applied to detect the HE4 level in the serum of the NC, EnHy and EnCa group. Re-sults: The expression of HE4 protein was higher in the EnCa group than in the NC and EnHy group, with statistical differences amongthe three groups ( P < 0.001 ). The median IOD of HE4 protein was lower in the group with stage Ⅰ endometrial carcinoma than in thegroup with the stage-Ⅱ and Ⅲ carcinoma. The differences in positive IOD expression among the three groups were statistically signifi-cant ( P < 0.001 ). The IOD of HE4 in endometrial carcinoma tissue was positively correlated with the FIGO staging ( P = 0.001 ). Thepreoperative median level of HE4 was significantly higher in EnCa group than in the NC and EnHy group ( P < 0.05 ). In EnCa group,the postoperative level of HE4 was significantly lower in the serum of EnCa group than the preoperative level ( P < 0.05 ). In endometri-al cancer group, the expression of HE4 protein in tissue was positively correlated with the preoperative serum HE4 levels. The preopera-tive serum HE4 levels were positively correlated with the FIGO staging and the level of CA125 in the serum ( P < 0.05 ). Conclusion:The elevated expression of HE4 can be a biomarker for endometrial carcinoma and can be an objective index for early auxiliary diagno-sis, evaluation of curative effect, and prognosis assessment of the carcinoma.Keywords Endometrial carcinoma; Human epididymis gene product 4 (HE4); Integrated optical density ( IOD )