Galectin-8 has a role in the biology of colon cancer, as its expression in cancerous tissue and its effects on migration of cancer cells indicate, report Nagy et al in the first study to establish its function since its cloning by the group. Galectin-8 belongs to a family of 12 galectins so far identified—β galactoside binding proteins thought to affect cell adhesion, proliferation, and migration in human colon cancer cells.

Using quantitative computer assisted microscopy and immuno histochemical staining, Nagy et al were able to show that galectin-8 was expressed significantly less in thin sections of cancerous tissue from 26 colon cancers than dysplastic tissue from 10 adenomas or normal human tissue from surgical resections or endoscopy—and least of all in the most invasive cancers (T3-4/N+/M+). It was also expressed in vitro in four human cancer cell lines—HCT-15, LoVo, CoLo201, and DLD-1—but less so in vivo in these same lines grafted into nude mice, and least in the fastest growing mouse xenografts, LoVo and DLD-1. When coated onto culture supports, galectin-8 was shown by computer assisted video microscopy to inhibit cell migration of the cancer cell lines—but only in those with the slowest growth in vivo, HCT-15 and CoLo201.

Galectin-8, this painstaking study shows, acts as a suppressor to slowly growing and less invasive colon cancers, indicating the importance of galectins other than galectin-1 and galectin-3, which, until now, have been the focus of most research.