Separate functions of α2β1 and α2β1 integrins in the metastatic process of human gastric carcinomaintegrins in the metastatic process of human gastric carcinoma

The expression of α2β1 and α3β1 integrins was studied immunohistochemically in 110 resected human gastric carcinomas. Formalin-fixed and paraffin-embedded samples were serially sectioned and stained with monoclonal antibodies specifically against the α2 and α3 subunits of β1 integrins. Approximately 27% of the tumors expressed α3β1 integrin, and 20% expressed α3β1 integrin. The expression of α3β1 integrin was associated with lymph node and liver metastases (P<0.05 andP<0.05, respectively), and the expression of α3β1 integrin was associated with liver and peritoneal metastases (P<0.005 andP<0.0005, respectively). A multivariate analysis by the logistic regression model revealed that the expression of α3β1 and/or α3β1 integrins was an independent factor related to liver metastasis, and that the expression of α3β1 integrin was as strong an influence on the formation of peritoneal metastases as the depth of invasion. The expression of α3β1 integrin also correlated with increased invasiveness of the tumor; however, there was no correlation between α2β1 integrin expression and the invasiveness. These results suggest that α2β1 and α3β1 integrins have separate influences on the metastatic properties of cancer cells.