UICC World Cancer Congress 2006

Objective:Estrogen receptor-related receptors (ERRs) are a subfamily of orphan nuclear receptors closely related to the estrogen receptors (ERs) and consist of three isoforms-á, â and g. In vitro researches showed ERRs could bind estrogen response elements (EREs) and interfere in the ER signal pathway. Therefore it might be associated with the estrogen-dependent diseases. The purpose of this study was to explore whether ERRs involved in the tumorigenesis of endometrial carcinoma and the relationship between ERRs and ER.

Methods:We examined the expression of ERRs in endometrial carcinoma tissues and normal endometrium tissues using semi-quantitative RT-PCR and immunohistochemistry. Clinicopathologic features including FIGO stage, histological grade, myometrial invasion and nodal metastasis were also reviewed. The statistical analysis was performed via SPSS 10.0 software.

Results:It showed that the mRNA levels of ERRá, â and ã were positively associated with the immunoreactivity respectively (P=0.009, P=0.014 and P=0.001). The expression rate and relative level of ERRá mRNA in ERá-positive endometrial carcinoma tissues were lower than ERá-positive normal endometrium tissues (P=0.049 and P=0.023, respectively). Compared with normal endometrium tissues, a higher expression level of ERRã mRNA was observed in ERá-positive endometrial carcinomas (P=0.014). Spearman's correlation analysis showed that the expression of ERRá mRNA significantly correlated with the FIGO stage (P=0.019) and myometrial invasion (P=0.043). Higher expression of ERRá mRNA was positively associated with more advanced FIGO stage and myometrial invasion. A negative correlation was observed between expression of ERRã mRNA and nodal metastasis (P=0.021).ERRá and ERRã are promising to be new prognostic factors in endometrial carcinoma.