We are interested in the characterization of genes whose expressions in the colon are modified during colorectal
carcinogenesis. Our approach was to establish the phenotype of a colon
tumor by partial sequencing of a large number of transcripts, then to select mRNAs of potential interest by differential screening with complex probes from normal or cancerous colon. In this paper, we report the cloning and sequencing of a
mRNA strongly underexpressed in
colorectal cancer. It corresponded to a
protein comprising 323
amino acids, that appeared to be human
galectin-4 on the basis of 76% and 79%
amino acid identity to the rat and pig counterparts, respectively. Tissue distribution analysis showed that its expression was restricted to the small intestine, colon and rectum.
Galectin-4 expression was compared in
tumor and normal adjacent colon of 19 patients. In 18 patients, the
mRNA concentration was 1.5-50-times lower in the
tumor. No significant correlation was observed between decreased expression of
galectin-4 and the degree of differentiation of the
tumor or Duke's state. These results suggest that decreased
galectin-4 mRNA expression may be an early event in colon
carcinogenesis. Among five cell lines derived from colon
carcinoma, only two (HT29 and LS174T) expressed
galectin-4 mRNA.