Expression of Beta-1 integrin in human gastric carcinomas - correlation with histological type and tumor progression

The expression of beta1 integrin, a subunit of cell adhesion receptor molecules, in human gastric carcinomas was examined by Northern blotting, Western blotting and immunohistochemistry. All the five gastric carcinoma cell lines expressed beta1 integrin mRNA and protein. Among them, TMK-1 cells expressed abnormal beta1 integrin protein with lower molecular weight. In gastric carcinoma cases, all the tumor tissues as well as corresponding non-neoplastic gastric mucosa expressed beta1 integrin mRNA and protein at various levels. Poorly.differentiated adenocarcinomas, especially Borrmann's type-4 or scirrhous carcinomas where the tumor cells proliferate diffusely with productive fibrosis, expressed beta1 integrin at higher level when compared to well differentiated adenocarcinomas. The level of beta1 integrin expression increased as the tumor stage progressed. Deeply invasive carcinomas showed a tendency to express beta1 integrin at higher level. These findings suggest that beta1 integrin might be an important determinant of development of scirrhous carcinoma and implicated in the invasive growth and the progression of gastric carcinomas.