Objective:To examine the expression of programmed cell death 1 (PD-1) and its ligand (PD-L1) in epithelial ovarian cancer (EOC) tissues, and investigate the correlation among their expression, clinicopathological features and prognosis.Methods:The specimens of 180 patients with EOC treated in the First Affiliated Hospital of Dalian Medical University from October 2002 to December 2013 were confirmed by pathological examination. The pathological tissue specimens of subtypes ，included 120 cases of serous carcinoma, 30 cases of mucinous carcinoma, 20 cases of endometrioid carcinoma, and 20 cases of clear cell carcinoma. The normal paracancerous tissues of 50 cases randomly selected from the 180 patients as control group. Immunohistochemical SP method was used to detect the expressions of both PD-1 and PD-L1 in epithelial ovarian cancer tissues, and the relationships among their expressions,the clinicopathological parameters and prognosis were respectively analyzed.Results:（1） PD-1 was expressed in lymphocytes infiltrated in EOC tissues, and PD-L1 was expressed in the cell membranes of cancer tissues. In all EOC cases, 33 cases (18.3%, 33/180) of both PD-1 and PD-L1 were highly expressed, and only 1 (2.0%, 1/50) of control group showed high expression. There was statistically significant difference between two groups ( P<0.01). (2) Among the four subtypes tissue specimens of EOC, the high expression rate of PD-1 was 25.0% (30/120) for serous carcinoma, 3/15 for endometrioid carcinoma, 0 (0/30) for mucinous carcinoma, and 0 (0/15) for clear cell carcinoma. The high expression rate of PD-L1 was 23.3% (28/120) for serous carcinoma, 3.3% (1/30) for mucinous carcinoma, 2/15 for endometrioid carcinoma, and 2/15 for clear cell carcinoma. Both PD-1 and PD-L1 expressions in the four sub-types of tissue specimens were significantly different ( P<0.05). The high expression rate of both PD-1 and PD-L1 was 9.2% (8/87) in the early stage and 26.9% (25/93) in the late stage. There was a statistically significant difference between the two groups ( P<0.01). Similarly, the expression of both PD-1 and PD-L1 were significantly higher in the cases of high-grade EOC （type Ⅱ） than those of low-grade （type Ⅰ） and in the cases of EOC distributed bilaterally than that distributed unilaterally, and there were statistically significant differences ( P<0.05). (3) The Kaplan-Meier survival analysis showed that the survival time were respectively 35 and 36 months in the cases with high expressions of both PD-1 and PD-L1, and the survival time were the same as 61 months in the cases with low expression of both PD-1 and PD-L1, and the comparison was statistically significant ( P<0.05). Conclusions:The expression levels of PD-1 and PD-L1 in EOC tissues are higher than those in adjacent tissues, especially in serous carcinomas. The expression of both PD-1 and PD-L1 is higher in specimens of the patients with advanced stages. The results showed that the high expression of both PD-1 and PD-L1 is an indicator of poor prognosis of patients suffering from EOC.

Objective To detect phosphorylated-extracellular signal-regulated kinase (p-ERK1/2) protein expression in epithelial ovarian cancer and cell lines,and to examine the effects of mitogen-activated protein kinase (MAPK) kinase (MEK) inhibitor AZD6244 on cell proliferation,apoptosis as well as cell cycle of ovarian cancer cells.To explore the function and significance of MAPK/extracellular signal-regulated kinase (ERK) signaling pathway in the development of ovarian cancer.Methods (1) A total of 104 cases of patients with ovarian cancer who accepted the treatment of gynecological surgery and being confirmed by pathological examination in First Affiliated Hospital,Dalian Medical University from January 2004 to December 2013 were selected.The expressions of p-ERK1/2 protein were detected by immunohistochemistry in ovarian cancer specimens,and the relationship between the expressions of p-ERK1/2 and the clinical features of patients was analyzed.(2) p-ERK1/2 and other related proteins were determined by western blot in various ovarian cancer cells,including SKOV3,OV2008,C13,A2780S,A2780CP,OVCAR4,OVCAR5,OVCAR8 and CAOV3 treated with or without MEK inhibitor.The cellular proliferation,apoptosis and cell cycle of ovarian cancer cells after treatment with MEK inhibitor were analyzed by methyl thiazolyl tetrazolium (MTT) assay and flow cytometry,respectively.Results (1) The immunohistochemical method showed that p-ERK1/2 between low grade serous carcinoma and clear cell carcinoma were not significantly higher expressed (P＞0.05).However,a lower level of the p-ERK1/2 expression were observed among high grade serous carcinoma,mucinous carcinoma and endometrioid carcinoma (all P＜0.05).There was no significant correlation between the protein expression of p-ERK1/2 and patients' age,pathological stage of surgery,and preoperative serum CA125 level (P＞0.05).(2) Western blot showed that the protein p-ERK1/2 was widely expressed in various ovarian cancer cell lines such as SKOV3,OV2008,C13,A2780S,A2780CP,OVCAR4,OVCAR5,OVCAR8 and CAOV3.After treatment with AZD6244 (5,10 μmol/L),the level of p-ERK 1/2 in OVCAR5 and OVCAR8 decreased significantly in dose-dependent manner.Additionally,we found a reduction of the expression level of cyclin D 1,caspase-3 and appeared cleaved poly adenosine diphosphate ribose polymerase (PARP) in OVCAR5 and OVCAR8,compared with control groups.MTT assays showed that OVCAR5,OVCAR8 and A2780S were differently inhibited in the dose-dependent manner after being treated with different concentrations of AZD6244 (0,2.5,5,10,25,50 and 100 μmol/L,all P＜0.05).Further tested by flow cytometry,the results showed that AZD6244 (5,10 μmol/L) was able to induce the apoptosis of OVCAR5,OVCAR8 and A2780S,as well as G0/G1 phase arrest,both in a dose-dependent manner (P＜0.05).Conclusions As the main active and functional unit of MAPK/ERK signaling pathway,p-ERK1/2 protein is expressed in both the tissues and various ovarian cancer cell lines.AZD6244 could down-regulated the expression of p-ERK1/2 in ovarian cancer cells,accompanied by the decreased proliferation and increased cell apoptosis of ovarian cancer cells.In conclusion,MAPK/ERK signaling pathway might play a role in the development and progression of ovarian cancer,and may be provide a novel option for molecular targeted therapies of the disease.