Abstract： Objective The purpose of this study was to evaluate gene amplification by chromogenic in situ hybridization (CISH) and the protein expression of Her-2/neu gene in patients with uterine papillary serous carcinoma ( UPSC) and to determine its prognostic value.Methods Thirty-six patients with confirmed pathologic diagnosis of UPSC in Cancer Hospital of Fudan University from Jan.1996 to Jan.2006,were analysed retrospectively.CISH was performed to assess Her-2/neu gene amplification,and protein expression was evaluated by immunohistochemistry (IHC).The prognostic factors were analyzed by log-rank test or Cox proportional hazard model.Results Among 36 cases with UPSC,13 patients (36.1% ) showed moderate staining (++) to strong staining (+++) for Her-2/neu protein,while amplification of the Her-2/neu gene by CISH was observed in 4 of the 36 (11.1% ) cases.Her-2/neu protein over-expression was significantly associated with advanced surgical stage and worse prognosis by univariate analysis ( P = 0.030 and P = 0.002,respectively),while the multivariate analysis shown that only Her-2/neu protein over-expression and deep myometrial invasion were associated with a poor prognosis ( P < 0.05 ).In 13patients with Her-2/neu protein over-expression,the mean survival period with chemotherapy was shorter than those without chemotherapy (20 vs.42 months,P = 0.370 ).Conclusion Her-2/neu protein over-expression is significantly associated with advanced surgical stage UPSC and poor survival outcome,and might reduce the chemotherapy sensitivity.