Abstract: Objective To explore the expression level of EphA1 in ovarian serous adenocarcinoma and analyze its correlation with clinicopathological characteristics， as to provide reference for screening a new indicator in ovarian serous adenocarcinoma for diagnosis and prognosis.
Methods The immunocytochemical method was employed to measure the expression of EphA1 in human ovarian cancer cell lines HO8910， SKOV3 and A2780 cells. The protein expression level of EphA1 in 76 ovarian serous adenocarcinoma tissues was detected by immunohistochemical staining. The results were divided into low-level expression（≤5） group and highlevel expression group（＞5） according to the immunohistochemical staining counting method. The relationships between the expression of EphA1 and clinicopathological characteristics were investigated. Results The expression of EphA1 protein was negative in HO8910 and SKOV3 cells but weakly positive in A2780 cell. Out of 76 tissue samples of ovarian serous adenocarcinoma， there were 33 cases（43.4％） with high-level expression and 43 cases（56.6％） with low-level expression， respectively. The expression of EphA1 protein was related with WHO and MDACC grading（P＜0.05）, but unrelated with clinical staging， metastasis， tumor location， tumor diameter and age（P＞0.05）. The median overall survival of highlevel expression group was 71.0 months， higher than 31.0 months of lowlevel expression group with significant difference（P＜0.05）.Conclusion Expression of EphA1 protein in ovarian serous adenocarcinoma is downregulated， and is related with high histological grade and poor prognosis. EphA1 protein may be a new index of diagnosis and clinical prognosis in ovarian serous adenocarcinoma.