Characteristics of colorectal carcinoma cells with high metastatic potential.

Malignant tumors shed large numbers of cells into the circulation, only a small fraction of which actually produce distant metastases. The cells comprising these tumors may be heterogeneous in many respects including their biological behavior. Inasmuch as colonic epithelial cells secrete mucins that reflect the state of cell differentiation, and differences in mucin structure may be detected by selective lectin binding, we used fluorescein isothiocyanate-conjugated lectins and fluorescence microscopy to analyze mucins secreted by primary colon cancers and metastases. In this way we hoped to determine whether differences exist in the glycoconjugates produced by metastatic and nonmetastatic cell populations. Out studies demonstrated that, in a given primary cancer, the mucin produced differed from that made by its metastases. Thus the vast majority of cells in primary tumors produced mucin that was specifically labeled by fluorescent peanut agglutinin (14 of 16 tumors). In contrast, 72% (37 of 51) of metastatic tumors produced mucin that did not bind peanut agglutinin (p less than 0.001). Colon cancer cells with high metastatic potential may therefore produce mucins that lack an exposed oligosaccharide receptor for this lectin.