Expression of the c-Met Proto-Oncogene and Integrin α5β1 in Human Gastric Cardia Adenocarcinoma

The hepatocyte growth factor receptor c-Met, a receptor tyrosine kinase, and Integrin alpha 5 beta 1, one of the main ECM receptors of hepatocytes have been reported to play important roles in tumor growth by activating mitogenic signaling pathways. In human gastric cardia adenocarcinoma, however, expression of the c-Met and Integrin alpha 5 beta 1 have not been reported. Here we examined the mRNA levels and protein expressions of these two genes and their relationship in human normal gastric cardia mucosa and primary carcinomas. Quantitative real-time PCR was used to analyze the mRNA expression of both c-Met and Integrin alpha 5 beta 1. The relationship between c-Met and Integrin alpha 5 beta 1 expression and the histologic characteristics of tumors were studied. Western blot analysis was performed to investigate the presence of c-Met and Integrin alpha 5 beta 1. The expression patterns of c-Met and Integrin alpha 5 beta 1 in 45 frozen slides of cardia adenocarcinoma were identified by immunohistochemistry. Our results indicate that the expression of c-Met and of Integrin alpha 5 beta 1 was significantly associated with tumor differentiation, TNM, and metastasis via the lymphogenic route. A significant positive correlation was also found between c-Met and Integrin alpha 5 beta 1 mRNA expression, suggesting that expression of c-Met and Integrin alpha 5 beta 1 has mechanical significance in the early stages of human gastric cardia adenocarcinoma.