Abstract: To discuss the expression of four biological parameters, namely, HER-2/neu, COX-2, PGE2, and P450arom, in endometrial carcinoma as well as to analyze their relationship in the expression patterns and all kinds of clinicopathologic factors. Methods: Reverse transcription polymerase chain reaction and ELISA were used to detect the expression of HER-2/neu, COX-2, P450arom, and PGE2 in normal endometrium, endometrial hyperplasia, and endometrial carcinoma. Results: The expression levels of HER-2/neu, COX-2, P450arom, and PGE2 were significantly higher in tumorous tissue than in nontumorous tissue ( P < 0.01 ). There was a positive correlation among the expression levels of HER-2/neu, COX-2, and P450arom in the tumor ( r = 0.931, r = 0.934, P < 0.05 ). COX-2 expression was positively correlated with that of P450arom in tumorous tissue ( r = 0.908, P < 0.05 ). There was also a correlation between the expression of COX-2 mRNA and PGE2 in the tumor ( r = 0.552, P <0.05 ). Conclusion: HER-2/neu, COX-2, P450arom, and PGE2 may have a synergistic effect on the oncogenesis and progression of endometrial adenocarcinoma.