Expression And Clinical Significance Of EphB2 In Human Pancreatic Cancer

Introduction and ObjectivePancreatic cancer is most frequently adenocarcinoma which is difficult to bedetected at early stage, with a 5-year survival rate of＜5%. To know the mechanism ofthe genesis and development of pancreatic cancer and look for an effective method fordiagnosis and treatment is our task. Persistent angiogenesis is needed in the course oftumors' occurrence and development. Many growth factors contribute to this course.Eph(Erythropoietin producing hepatoma) make up the largest subgroup of receptortyrosine kinases(RTK) family. The Eph family have been divided into A and Bsubgroup according to the homology of extracellular structure field, structure and theaffinity for ligand. At present, they play an important role in controlling angiogenesisand regulating tumorigenesis growth. EphB2 is the most important menber in thisfamily. It has been proved that they are highly expressed in many kinds of tumors. Fewhas studied their expressions in pancreatic cancer. In this study ,we checked theexpression of EphB2 in pancreatic cancer, compared them with normal pancreatictissue by immtmohistochemistry. We analyzed biological significance of EphB2 inpancreatic cancer, and provide evidences for the gene therapy of pancreatic cancer infuture.MethodsThe 24 specimens of pancreatic cancer were selected from Feberary, 2003 toFeberary, 2006 at the Second Hospital of China Medical University, and 6 specimensof normal pancreatic tissue were collected as negative control. We detected the expression of EphB2 in the tumor and normal tissue in immunologic histochemistrymethods. EphB2 scoring was used for the valuation of EphB2 expression as counted bythe sum of staining intensity score, with 0=no staining, 1=weak staining, 2=moderatestaining, 3=strong staining in the relevant cell types and positive cell score with 0 forpositive staining cells 0% of all cells, 1 for＜25%, 2 for 25-50%, and 3 for＞50%. Thecases with EphB2 score＞2 was defined as EphB2 positive cases, those with VEGFscore≤2 as negative cases. Statistic analysis was completed with statistic softwareSPSS11.0, and K-S test, analysis of variance, SNK test and t test were used. P＜0.05,was as the level for statistical significance.ResultsCells staining for EphB2 show yellow or brown granules in cytoplasm whichmainly distribute in carcinoma cells and less present in normal tissues and tissuessurrounding carcinoma. EphB2 positive rate (66.67%, 16/24) and EphB2 score (3.08±1.349) of pancreatic cancer group are obviously higher than control group (P＜0.01). But there are no significant differences between patients with high, middle and lowdifferentiated carcinoma (P＞0.05). EphB2 expression in the group with lymphaticmetastasis is significantly higher than that without lymphatic metastasis(P＜0.05).ConclusionThe expression of EphB2 in the pancreatic cancer tissue was significantly higherthan that in the normal tissue, suggest that EphB2 may have relationship with the thegenesis and development of pancreatic cancer. It is obviously higher in metastasisgroup than in non-metastasis group which suggest the association between EphB2expression and lymphatic metastasis in pancreatic cancer and that EphB2 may be ableto promote the metastasis of tumor cells in pancreatic cancer.