EXPRESSION OF 32-KDA LAMININ-BINDING PROTEIN MESSENGER-RNA IN COLON-CANCER TISSUES

Colorectal cancer initiation and progression are associated with stepw ise genetic alterations. We and others have shown that a gene encoding for a 32-kDa putative laminin-binding protein (LBP-32) is overexpress ed during colorectal cancer progression by Northern blots analysis. No rthern blots cannot indicate the heterogeneity of expression from cell to cell and the distribution pattern of gene expression within a give n tumor. In order to overcome these problems, we examined the LBP-32 m RNA expression in colorectal carcinomas by in situ hybridization. LBP- 32 mRNA expression in 30 cases of primary and metastatic colorectal ca ncers and their respective adjacent normal tissues were detected by in situ hybridization using S-35-UTP radiolabeled antisense riboprobes. The results showed that LBP-32 mRNA was expressed at a low level in th e normal colonic mucosa adjacent to the tumor compared with colon canc er tissues. Its expression in poorly differentiated colorectal cancer was much higher than that in well- and moderately differentiated color ectal cancer. More importantly, the LBP-32 mRNA was expressed more hig hly in the invasive lesions of the cancer and liver metastases compare d with the cancer lesions in situ. Our results imply that in situ hybr idization is a powerful tool in evaluating the changes in gene express ion in the cancer cells and LBP-32 mRNA expression is related to progr ession, invasion, and metastasis of colorectal cancer. (C) 1996 Academ ic Press, Inc.