2047

EPHB1

EPH receptor B1;EPHB1;EPH receptor B1

EK6|EPH-like kinase 6|eph tyrosine kinase 2|ephrin type-B receptor 1|neuronally-expressed EPH-related tyrosine kinase|soluble EPHB1 variant 1|tyrosine-protein kinase receptor EPH-2

3q21-q23

protein-coding

OBJECTIVE: EphB1 is a member of the Eph family of receptor tyrosine kinases that is involved in embryonic nervous and vascular system development. Over- or underexpression of certain Eph receptors has been found in some cancer samples compared to normal tissue. expression of Eph receptors is related to malignant transformation, metastasis, differentiation, and prognosis of cancers. Recently, the EphB subfamily has been shown to be involved in the tumorigenesis of colorectal cancer. In the present study, expression of the EphB1 transcript and protein in gastric carcinoma samples was determined to investigate the roles of EphB1 in development, progress and prognosis of gastric carcinoma. METHODS: Quantitative real-time reverse transcriptase-polymerase chain reaction and immunohistochemical staining were used. RESULTS: The EphB1 transcript was overexpressed in 68.9% (42/61) and underexpressed in 14.8% (9/61) of cases. However, the expression of protein was greatly different from the transcript expression, with overexpression and underexpression being 17.2% (10/58) and 44.8% (26/58), respectively. In addition, we showed that underexpression of EphB1 protein is significantly associated with invasion, stage and metastasis in gastric carcinomas. CONCLUSION: EphB1 may have a tumor-suppressive role in gastric cancer.

Aberrant expression of receptors tyrosine kinase of Eph gene in human cancers is extensively documented. We previously found that EphB1 subtype is down-regulated in gastric cancer and colorectal cancer. Fore the more, decreased expression of EphB1 is related to invasion and metastasis in cancers. There is no published data regarding the role of EphB1 in ovarian cancer, which is the focus of the present study. The expression of EphB1 protein was determined in tissues from 74 patients with serous ovarian carcinoma and 12 normal ovarian epithelial tissues. The expression level of EphB1 protein in serous ovarian carcinoma was analyzed with respect to clinicopathological parameters and survival. EphB1 protein was positively stained in 12 normal ovarian epithelial samples, and negatively stained in 32 out of 74 (43.2%) serous ovarian cancers. Loss of expression of EphB1 protein was associated with higher tumor grade (P=0.006), metastasis (P=0.049) and high proliferative index Ki67 expression (P=0.022), but not with FIGO stage (P=0.0937), age at diagnosis (P=0.624), and diameter of carcinoma (P=0.108). In addition, loss of EphB1 protein in serous ovarian carcinoma was associated with a significantly worse overall survival (P=0.015). Our data indicate that loss of EphB1 protein is associated with metastasis and poorer survival in patients with serous ovarian cancer. EphB1 may be used as a prognostic marker and a therapeutic target in serous ovarian carcinoma.