Expression of a Mr 32,000 laminin-binding protein messenger RNA in human colon carcinoma correlates with disease progression.

Cell surface receptors for laminin may play an important role in tumor migration and metastasis. To evaluate laminin receptor/laminin-binding protein expression in human colon carcinoma, surgical specimens of primary colon cancers and liver metastases were examined by blot hybridization of total RNA with a complementary DNA clone which encodes a Mr 32,000 human laminin-binding protein. The mRNA level of the laminin-binding protein was higher in primary colon carcinoma than in adjacent normal colonic epithelium in 20 of 21 cases. In all 6 cases of colon cancer liver metastases, the laminin-binding protein mRNA level was more than 3-fold greater in tumor than in adjacent normal liver tissue. The tumor/normal ratio of this laminin-binding protein mRNA expression in primary colon cancer has significant correlation with Dukes' classification (P less than 0.001). Our results suggest that mRNA expression of the laminin-binding protein may be a marker of human colorectal cancer progression and biological aggressiveness.