Loss of expression of EphB1 protein in gastric carcinoma associated with invasion and metastasis.

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.